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Although various bismuth (Bi) electrode materials are reported to assemble aqueous alkaline rechargeable batteries (AARBs) owing to desirable potential window and high theoretical capacity, the Bi‐based electrode materials are still confronted with by their "death space" and poor stability. Herein, a zero‐dimensional/two‐dimensional (0D/2D) amorphous/crystalline BiOx‐Bi heterostructure is successfully synthesized by a one‐step reduction method for achieving nearly theoretical capacity. Under proper NaBHNaBH4 content, the Bi33+ is reduced to form ultra‐thin 2D metallic bismuth nanoflakes (Bi‐nf), and incompletely reduced amorphous 0D BiOx nanodots are embedded in Bi‐nf to form the target BiOx/Bi‐nf heterostructure. The embedded 0D nanodots inhibit the aggregation of 2D Bi‐nf, accelerate the mass transport rate with more oxygen vacancies and pores at heterogeneous interface, and the active centers of amorphous nanodots and ultrathin nanoflakes are recognized as completely accessible which is benefit for up to theoretical capacity. Accordingly, the optimized 0D/2D amorphous/crystalline BiOx‐Bi‐nf heterostructure electrode presents an admirable capacity of 350 mAh g−1 at 1 A g−1 and outstanding capacity retention of 79.9% at 20 A g‐1. Moreover, the assembled BCNP (basic cobalt/nickel phosphate)//BiOx/Bi‐nf battery exhibits exceptional energy density of 191.64 Wh kg‐1 at 1.28 kW kg‐1 power density and durable stability (80% after 14000 cycles). [ABSTRACT FROM AUTHOR]

Rechargeable Zn-air batteries are considered to be an effective energy storage device due to their high energy density, environmental friendliness, and long operating life. Further progress on rechargeable Zn-air batteries with high energy density/power density is greatly needed to satisfy the increasing energy conversion and storage demands. This review summarizes the strategies proposed so far to pursue high-efficiency Zn-air batteries, including the aspects of the electrocatalysts (from noble metals to non-noble metals), the electrode chemistry (from the oxygen evolution reaction to the organic oxidation reaction), electrode engineering (from powdery to free-standing), aqueous electrolytes (from alkaline to non-alkaline) and the battery configuration (from liquid to flexible). An essential evaluation of electrochemistry is highlighted to solve the challenges in boosting the efficiency of rechargeable metal-air batteries. In the end, the perspective on current challenges and future research directions to promote the industrial application of rechargeable Zn-air batteries is provided. [ABSTRACT FROM AUTHOR]

The main challenges faced by aqueous rechargeable nickel‐zinc batteries are their comparatively low energy density and poor cycling stability, mainly due to the limited capacity and reversibility of existing Ni‐based cathodes. Moreover, the preparation procedures of these cathodes are complex and not easily scalable, which makes them less promising for large‐scale energy storage. Herein, we utilized MXene as a functional additive to effectively improve the electrodeposition preparation of NiCo layered double hydroxides (LDH). Benefiting from the improved interfacial contact between nickel foam (NF) and platting solution and the enhanced ionic conductivity of platting product based on MXene additives, the resulting binder‐free NiCo LDH electrode can achieve ultrahigh areal loading (~65 mg cm−2) with abundant active surface for redox reactions and maintained short transport pathway for ion diffusion and charge transfer. Furthermore, the as‐fabricated alkaline NiCo LDH‐based battery delivers high discharge capacity, up to 20.2 mAh cm−2 (311 mAh g−1), accompanied by remarkable rate performance (9.6 mAh cm−2 or 148 mAh g−1 at 120 mA cm−2). Due to the high structural and chemical stability of MXenes/LDH‐based electrode, excellent cycling life can also be achieved with 88.6 % capacity retention after 10000 cycles. In addition, ultrahigh areal energy density (31.2 mWh cm−2) and gravimetric energy density (465 Wh kg−1) can be simultaneously achieved. This work has inspired the design of advanced cathode materials to develop high‐performance aqueous zinc batteries. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are promising electrode materials for alkaline electrochemical energy storage (EES). However, their low capacity, sluggish rate performance, and limited cycle life significantly hinder practical applications. This study unlocks the direct deprotonation reaction pathway for LDH materials through theoretical calculations. Guided by this insight, a novelly hierarchical composite (LDH−TPA) with various dimensions and components is fabricated by introducing terephthalic acid (TPA), serving as a superior cathode material for alkaline EES devices. Experimental results and theoretical investigations reveal the transformation process for metal–organic framework quantum dots (MOF−QDs) and the enhanced mechanism of reaction kinetics in the LDH−TPA electrode. Benefiting from the reduced deprotonation barrier, optimized electronic structure, and fast electrons/ions transport rates, the LDH−TPA1 electrode demonstrates a high specific capacity of 267 mAh g−1 at 1 A g−1 and retains 167 mAh g−1 even at 20 A g−1, along with excellent cycling stability. Furthermore, an alkaline nickel−zinc battery (AZB) with LDH−TPA1 cathode is assembled, achieving a lifespan exceeding 3400 cycles, and a high energy density of 341.3 Wh kg−1 at a power density of 1640.9 W kg−1. This study is expected to provide new insight into the modification of LDHs and the advancement of alkaline energy systems. [ABSTRACT FROM AUTHOR]

Aqueous nickel‐based batteries, particularly nickel‐organic batteries, are promising candidates for large‐scale energy storage applications owing to their environmental friendliness, abundant resources, and intrinsic safety. However, organic anode materials suffer from serious dissolution in electrolytes during discharge/charge processes and ampere‐hour‐scale nickel‐organic batteries are still absent. Here, phenazine (PZ) is screened as the anode and utilizes 10 m KOH as the electrolyte to construct ampere‐hour‐scale PZ/Ni(OH)2 batteries to demonstrate the practicability. In situ, UV–vis and molecular dynamics simulations demonstrate the inhibited dissolution of PZ in high‐concentration of 10 m KOH. The PZ anode can provide a high initial specific capacity of 281.6 mAh g−1 at 0.5 C with a Coulombic efficiency of 98.6% and ultralong cycle life with a capacity retention of 74.3% after 14 000 cycles at 30 C. Moreover, the fabricated pouch‐type PZ/Ni(OH)2 battery with a high PZ mass‐loading of 48 mg cm−2 delivers a capacity of 1.23 Ah and achieves a high energy density of 50 Wh kg−1 (based on the total mass of the cell). The abundant resources, excellent stability, and cost‐effectiveness of phenazine endow nickel‐organic batteries with promising potential for large‐scale energy storage applications. [ABSTRACT FROM AUTHOR]

The capacity and cycling performance of cathodes are key factors in aqueous zinc batteries (AZBs). The search for cathode materials with long cycle lives and high specific capacities is of paramount importance. In this study, a bimetallic telluride with a hollow polyhedral structure was synthesized using a hydrothermal method followed by vapor deposition. This composite exhibits high conductivity, facilitates rapid diffusion of electrolyte ions into the interior, and accelerates redox reactions, thereby enhancing electrochemical performance. The CoTe2 -NiTe2 electrode demonstrates an impressive specific capacity of 188.8 mAh/g at 1 A/g, highlighting its efficiency in storing a significant amount of charge per unit mass during electrochemical reactions. The assembled CoTe2 -NiTe2//Zn battery shows favorable capacity retention (76.4%) after 10000 cycles. The energy density is remarkably high, reaching 290.3 Wh/kg, while maintaining a power density of 1.75 kW/kg. This bimetallic telluride strategy holds great promise as an alternative cathode for AZBs. [ABSTRACT FROM AUTHOR]

A new atomic-level strategy is introduced to finely optimize the OH− adsorption/desorption capability of β-Ni(OH) 2 through tailoring the 3d-orbital occupancy of Ni center via Co and Cu co-doping. [Display omitted] • The 3d-orbital electron occupancy of Ni species in β-Ni(OH) 2 can be optimized. • The interaction mechanism between OH− and Ni(OH) 2 is fully studied. • Co-Cu-Ni(OH) 2 electrode delivers a good capacity of 170.8 mAh g−1 and 2.3 mAh cm−2. The capacity and cycling stability of β-Ni(OH) 2 -based cathodes in aqueous alkaline Ni-Zn batteries are still unsatisfactory due to their undesirable OH− adsorption/desorption dynamics during the electrochemical redox process. To settle this issue, we introduce a new atomic-level strategy to finely modulate the OH− adsorption/desorption of β-Ni(OH) 2 through tailoring the 3d-orbital occupancy of Ni center by Co/Cu co-doping (denoted as Co-Cu-Ni(OH) 2). Both experimental outcomes and density functional theory calculations validate that the co-doping of Co and Cu endows the Ni species in Co-Cu-Ni(OH) 2 with appropriate proportion of the unoccupied 3d-orbital, leading to optimized adsorption/desorption strength of OH−. As anticipated, the Co-Cu-Ni(OH) 2 electrode demonstrates superior performance, achieving an areal capacity of 0.83 mAh cm−2 and a gravimetric capacity of 164.3 mAh g−1 at ∼50 mA cm−2 (10 A g−1). Furthermore, it sustains an impressive capacity of 170.8 mAh g−1 (2.3 mAh cm−2) at a high mass loading of 13.5 mg cm−2, alongside a long-term cycling performance over 1000 cycles. The assembled Co-Cu-Ni(OH) 2 //Zn cell is able to provide a peak energy density of 0.98 mWh cm−2 and excellent durability. This work highlights the potential of an orbital engineering strategy in the development of next-generation high-capacity and durable energy storage materials. [ABSTRACT FROM AUTHOR]

In this work, we study and compare the electrochemical performance of Li-ion battery (LIB) with and without a BiFe0.95Cu0.05O3 thin film coating. The BiFe0.95Cu0.05O3 thin film is deposited on both LiNi0.5Mn0.3Co0.2O2 (NMC532) cathode and graphite anode electrodes using radio frequency magnetron sputtering. By using galvanostatic charge–discharge measurements, we observe that, in contrast to LIB without BiFe0.95Cu0.05O3 coating, the charging curve of LIB with BiFe0.95Cu0.05O3 coating exhibits a counterintuitive negative slope of the negative electron compressibility (NEC) with a rate of NEC equal to −16.36 × 10−11 meV per electron per cm2. Importantly, we find that the NEC effect has the potential to enhance the energy density in LIB with BiFe0.95Cu0.05O3 coating. The energy density of the first discharge cycle is dramatically increased from 190 Wh/kg for pristine LIB to 255 Wh/kg for LIB coated with the BiFe0.95Cu0.05O3 film. We suggest the origin of this with the change in Mott gap and a concept to apply the NEC effect for enhancing energy density LIB batteries. [ABSTRACT FROM AUTHOR]

Alkaline zinc‐ferricyanide flow batteries are efficiency and economical as energy storage solutions. However, they suffer from low energy density and short calendar life. The strongly alkaline conditions (3 mol L−1 OH−) reduce the solubility of ferri/ferro‐cyanide (normally only 0.4 mol L−1 at 25 °C) and induce the formation of zinc dendrites at the anode. Here, we report a new zinc‐ferricyanide flow battery based on a mild alkalescent (pH 12) electrolyte. Using a chelating agent to rearrange ferri/ferro‐cyanide ion‐solvent interactions and improve salt dissociation, we increased the solubility of ferri/ferro‐cyanide to 1.7 mol L−1 and prevented zinc dendrites. Our battery has an energy density of ~74 Wh L−1catholyte at 60 °C and remains stable for 1800 cycles (1800 hours) at 0 °C and for >1400 cycles (2300 hours) at 25 °C. An alkalescent zinc‐ferricyanide cell stack built using this alkalescent electrolyte stably delivers 608 W of power for ~40 days. [ABSTRACT FROM AUTHOR]

While alkaline Zn batteries, like traditional rechargeable aqueous batteries, boast an advantage in terms of energy density, their progress has been hampered by concerns related to the anode. These concerns include issues like Zn dendrites, self‐corrosion, passivation, shape change, and the hydrogen evolution reaction (HER). To tackle these challenges, we have introduced a nanostructuring approach for the anode, employing carbon‐coated ZnO nanoparticles (ZnO@C) as the active material. In this study, we synthesized ZnO@C nanoparticles in an environmentally sustainable and scalable manner to address passivation and dissolution issues jointly. Nanoscale ZnO particles effectively prevent passivation, while carbon shell slows down the dissolution of zincate. The Zn anode exhibits a significant performance boost when compared to Zn foil and bare ZnO nanoparticles, even when subjected to demanding conditions (without the use of ZnO‐saturated electrolyte). This rechargeable Zn anode marks a significant step toward the realization of practical, high‐energy rechargeable aqueous batteries, such as Zn‐air batteries. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries (ARBs) are generally safer than non-aqueous analogues, they are also less-expensive, and more friendly to the environment. However, the inherent disadvantage of the narrow electrochemical window of H2O seriously restricts the energy density and output voltage of ARBs, especially aqueous rechargeable Fe-based batteries. Herein, we introduce a new battery system: the anode contains C@Fe/Fe2O3 composite, which is interfaced with an alkaline electrolyte; the cathode contains LiMn2O4 in contact with a neutral electrolyte. A Li+-conducting membrane is carefully selected to decouple the electrode-electrolyte, which effectively widens the electrochemical window to above 2.65 V, thereby enables an aqueous rechargeable iron battery. Its average output voltage is 1.83 V and its energy density is 235.3 Wh/kg at 549 W/kg. In this work, we propose the energy storage mechanism with the aid of density functional theory (DFT). The calculated reduction potential of the anode agrees with the experimental value. Furthermore, this battery system demonstrates long cycle lifespan of approximately 2500 cycles at 2 A/g, corresponding to a capacity retention of 82.1%. These results are very far superior than those of mainstream aqueous rechargeable Fe-based batteries, which guarantee future investigation for storing electricity energy. [ABSTRACT FROM AUTHOR]

The development of low‐cost and high‐performance iron (Fe)‐based anode materials is of great significance for rechargeable aqueous batteries. Herein, a FeS@Fe foam anode with crosslinked nanoflake array structure is fabricated. Being adopted as alkaline anode, FeS@Fe foam delivers enhanced areal capacity of 31.1 mAh cm−2 (at 50 mA cm−2), which is ≈1.5 times that of the‐state‐of‐the‐art literatures. The scaled‐up tests further reveal the higher capacity (800.7 mAh) and current density (1.25 A) with the area of 25 cm2. The FeS@Fe foam anode sustains intact after 270‐day cycles, demonstrating excellent durability. The assembled FeS//NiO single battery provides a superior areal energy density of 300.7 Wh m−2 at 500 W m−2. The reaction mechanism and electrode kinetics are revealed by combining in/ex situ techniques and DFT calculations. Experimental results and in/ex situ characterizations validate that excellent structural stability and high areal capacity are attributed to effective interface regulation and improved energy storage mechanism, respectively. This work pushes the advanced Fe‐based electrode to a superior level among these available alkaline solid‐state batteries. [ABSTRACT FROM AUTHOR]

Molybdate intercalation significantly reduces the thickness of cobalt–nickel layered hydroxide, greatly increases its specific surface area, regulates its pore distribution, increases the crystal plane spacing, promotes the diffusion rate of hydroxide in it, and increases its specific capacity. Meanwhile, the bilayered MCN-LDH@CP electrode significantly improved the areal energy density and peak power density and cycle stability of the CoNi//Zn battery. The quasi-solid-state MCN-LDH@CP//Zn battery can still charge a mobile phone even when hammered and pierced, showing excellent safety and reliability. [Display omitted] Seeking cathode materials with high areal capacity and excellent cycling tolerance is a key step to develop aqueous rechargeable zinc-based alkaline batteries with high energy density, power density and excellent stability. Here, the bilayered cathode composite (MCN-LDH@CP) of molybdate intercalated cobalt–nickel layered hydroxide nanosheets (MCN-LDH) grown on cobalt phosphate octahydrate microsheet (CP) was prepared by a two-step hydrothermal process. Molybdate intercalation significantly reduces the thickness of cobalt–nickel layered hydroxide, greatly increases its specific surface area, regulates its pore distribution, increases the crystal plane spacing, promotes the diffusion rate of hydroxide in it, and increases its specific capacity. Meanwhile, the bilayered MCN-LDH@CP electrode significantly improved the areal energy density (2.89 mWh/cm2) and peak power density (111.22 mW/cm2) and cycle stability (97.8 % after 7000 cycles) of the CoNi//Zn battery. The excellent stability is mainly due to the fact that the MCN-LDH overlay inhibits the loss of P element of CP and improves the structural stability of the sample. The quasi-solid-state MCN-LDH@CP//Zn battery can still charge a mobile phone even when hammered and pierced, showing excellent safety and reliability. This work opens a new avenue to develop CoNi//Zn batteries with high energy density, power density and excellent tolerance. [ABSTRACT FROM AUTHOR]

The addition of zinc can induce the formation of polymetallic (Zn-Ni-Co) carbonate hydroxides/hydroxides (MCHs/M(OH) 2) heterostructure nanosheet array with rich defect structures on Ni foam as a superior cathode (ZNC/NF) for alkaline aqueous rechargeable Zn-based batteries (AAZBs). The as-made binder-free cathode offers an extremely high mass loading of 9.2 mg cm−2, exhibiting excellent areal capacities and energy densities. [Display omitted] Developing high mass loading cathodes with high capacity and durable life cycles is greatly worthwhile and challenging for alkaline aqueous rechargeable Zn-based batteries (AAZBs). Herein, we demonstrate an efficient zinc-induced strategy to rationally develop Zn-Ni-Co carbonate hydroxides/hydroxides heterostructure nanosheet array with an extremely high mass loading of 9.2 mg cm−2 on Ni foam (ZNC/NF) as such a superior cathode for AAZBs. It is discovered that Ni-Co hydroxide nanowires can be transformed into Zn-Ni-Co carbonate hydroxides/hydroxides heterostructure nanosheet with rich defect structures after the introduction of Zn during the synthetic process. The formed heterostructures and rich defect structures can enhance ion and electron transfer efficiency, thus ensuring the excellent electrochemical performance under high loading condition. Consequently, the ZNC/NF//Zn battery shows an outstanding areal capacity of 2.1 mAh cm−2 at 5 mA cm−2, with an ultrahigh energy density of 3.6 mWh cm−2. Moreover, the battery can still retain a high capacity of 0.42 mAh cm−2 after 5000 cycles at 50 mA cm−2, suggesting strong long-term cycling stability. This research enables pave the way for the rational design and manufacture of advanced electrode materials with large mass loadings. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐ion micro‐batteries (AZMBs) have been recently shown to be promising integrated and safe micropower sources for portable electronics but with wide commercial adoption greatly constrained by their relatively low areal capacity. Although increasing the electrode thickness is proposed, the performance is compromised due to sluggish reaction kinetics, slow ion diffusion rate, and underutilization of active materials. Herein, the technique of utilizing a 3D thick‐network electrode, consisting of closely interweaved MnO2 nanowires (MnO2 NWs), silver nanowires (AgNWs), and carbon nanotubes (CNTs) is presented. The technique readily enables electrode realization up to a thickness of 351 µm, where the porous structure, high hydrophilicity, and fast electrolyte infiltration jointly contribute to fast kinetics. Matching with a Zn metal anode, the prototyped AZMBs acquire an ultra‐high areal capacity/power density of 809 µAh cm−2/1951 µW cm−2. Additionally, as MnO2 NWs and AgNWs collectively participate in the reaction as active substances, the AZMBs deliver dual voltage plateaus to further improve the areal energy density, realizing a maximum value of 896 µWh cm−2. The 3D thick‐network electrode supporting dual working voltage plateaus can provide a path forward for developing AZMBs with simultaneously ultra‐high areal capacity and energy density. [ABSTRACT FROM AUTHOR]

Aqueous sodium-ion batteries are practically promising for large-scale energy storage, however energy density and lifespan are limited by water decomposition. Current methods to boost water stability include, expensive fluorine-containing salts to create a solid electrolyte interface and addition of potentially-flammable co-solvents to the electrolyte to reduce water activity. However, these methods significantly increase costs and safety risks. Shifting electrolytes from near neutrality to alkalinity can suppress hydrogen evolution while also initiating oxygen evolution and cathode dissolution. Here, we present an alkaline-type aqueous sodium-ion batteries with Mn-based Prussian blue analogue cathode that exhibits a lifespan of 13,000 cycles at 10 C and high energy density of 88.9 Wh kg−1 at 0.5 C. This is achieved by building a nickel/carbon layer to induce a H3O+-rich local environment near the cathode surface, thereby suppressing oxygen evolution. Concurrently Ni atoms are in-situ embedded into the cathode to boost the durability of batteries. Aqueous sodium-ion batteries show promise for large-scale energy storage, yet face challenges due to water decomposition, limiting their energy density and lifespan. Here, the authors report a cathode surface coating strategy in an alkaline electrolyte to enhance the stability of both electrolyte and battery. [ABSTRACT FROM AUTHOR]

Mg–air batteries have high theoretical energy density and cell voltage. Their use of environmentally friendly salt electrolyte and commercially available magnesium materials determines their acceptable technical and economic efficiency, safety, and ease of operation. However, the practical applicationsof Mg–air batteries arevery limited due to the polarization of magnesium anodes and the batteries' low Faraday efficiency. In this study, we considered the possibility of designingan Mg–air battery withincreased power by adapting engineering solutions developed for an Al–air battery with alkaline electrolytes. To increase the specific power of the battery, it was proposed that the internal resistance of the battery maybe reduced using a concentrated salt electrolyte. We investigated the discharge performance of a commercial alloy of AZ31 type in 15 wt.% NaCl electrolyte at current densities of 40–120 mA/cm2. The influence of a small addition of sulfosalicylic acid into the electrolyte on the discharge performance of the anode alloy was studied as well. The estimated values of the energy characteristics of the 0.5 kW Mg–air battery were compared with those of an Al–air battery with an alkaline electrolyte. [ABSTRACT FROM AUTHOR]

A well-balanced micro-meso-macropore Fe-NC-C 3 N 4 catalyst with Fe-N 4 moieties is constructed via the strategy consisting of the space confinement and pore-making engineering, showing superior ORR and OER activity. The homemade liquid and flexible solid-state zinc-air batteries demonstrate excellent performance in terms of open-circuit voltage, discharging specific capacity, and long-term durability. [Display omitted] Exploring efficient, easy-to-manufacture, and inexpensive bifunctional electrocatalysts with abundant accessible active sites is crucial for rechargeable zinc-air batteries (ZABs). Herein, we report the strategy consisting of the space confinement and pore-making engineering to fabricate single-atom catalyst enriched with Fe-N 4 sites anchored on N -doped hierarchically porous carbon (Fe-NC-C 3 N 4). The optimized Fe-NC-C 3 N 4 exhibits excellent oxygen reduction/evolution reaction (ORR/OER) activities with a half-wave potential (E 1/2) of 0.90 V vs. RHE and a promising low overpotential of 0.305 V vs. RHE at 10 mA·cm−2 in alkaline electrolyte. These superior catalytic activities are attributed to the combined effect between the atomic active sites and the well-balanced micro-meso-macropore structures. The homemade liquid Zn-air battery (ZAB) assembled with Fe-NC-C 3 N 4 catalyst displays a power density of 133.59 mW·cm−2 and a significant energy density of 882.58 mAh·g−1, exceeding those of the equipment with commercial Pt/C-RuO 2 (56.82 mW·cm−2 and 643.87 mAh·g−1, respectively). Particularly, the corresponding flexible wearable ZAB manifests outstanding foldability and cyclical stability. This work opens a new perspective for the structural design of single-atom catalysts in the energy storage and conversion area. [ABSTRACT FROM AUTHOR]

Silicon–air batteries (SABs) are attracting significant attention for their potential as high‐energy‐density electrochemical storage devices. One of the main limitations for the commercial use of alkaline SABs is the high corrosion, which results in a low conversion efficiency. Herein, the aim is to examine the influence of polyethylene glycol (PEG) on the conversion efficiency of SABs, shedding light on key factors affecting their performance. SABs using KOH as electrolyte at two concentrations, 0.5 and 2.0 mol L−1, are investigated. The results show that replacing part of the water in the alkaline electrolyte with PEG changes the etching behavior from anisotropic to polishing and increases the specific energy density by 53% and 123% in 0.5 and 2 mol L−1 KOH electrolytes, respectively. [ABSTRACT FROM AUTHOR]

Alkaline aqueous zinc-ion batteries possess a wider potential window than those in mildly acidic systems; they can achieve high energy density and are expected to become the next generation of energy storage devices. In this paper, a hollow porous P-NiCo2O4@Co3O4 nanoarray is obtained by ion etching and the calcination and phosphating of ZiF-67, which is directly grown on foam nickel substrate, as a precursor. It exhibits excellent performance as a cathode material for alkaline aqueous zinc-ion batteries. A high discharge specific capacity of 225.3 mAh g−1 is obtained at 1 A g−1 current density, and it remains 81.9% when the current density is increased to 10 A g−1. After one thousand cycles of charging and discharging at 3 A g−1 current density, the capacity retention rate is 88.8%. Even at an excellent power density of 25.5 kW kg−1, it maintains a high energy density of 304.5 Wh kg−1. It is a vital, promising high-power energy storage device for large-scale applications. [ABSTRACT FROM AUTHOR]

The battery chemistry aiming for high energy density calls for the redox couples that embrace multi-electron transfer with high redox potential. Here we report a twelve-electron transfer iodine electrode based on the conversion between iodide and iodate in aqueous electrolyte, which is six times than that of the conventional iodide/iodine redox couple. This is enabled by interhalogen chemistry between iodine (in the electrode) and bromide (in the acidic electrolyte), which provides an electrochemical-chemical loop (the bromide-iodate loop) that accelerates the kinetics and reversibility of the iodide/iodate electrode reaction. In the deliberately designed aqueous electrolyte, the twelve-electron iodine electrode delivers a high specific capacity of 1200 mAh g−1 with good reversibility, corresponding to a high energy density of 1357 Wh kg−1. The proposed iodine electrode is substantially promising for the design of future high energy density aqueous batteries, as validated by the zinc-iodine full battery and the acid-alkaline decoupling battery. Enhancing energy density of batteries is a crucial focus within the field of energy storage. Here, the authors introduce a twelve-electron conversion iodine cathode (iodide/iodate) for high energy density zinc-iodine batteries, achieved through interhalogen chemistry in an acidic aqueous electrolyte. [ABSTRACT FROM AUTHOR]

Nickel–cobalt Prussian blue analogues (Ni–Co PBAs) suffer from structural instability in neural and alkaline electrolytes due to the dissolution of metal cations and cyanide anions caused by external H2O attack, resulting in capacity degradation and restricted life span. Herein, in this work, Ni–Co PBA quantum dots embedded in N-doped carbon (CC-Ni–Co PBA) were synthesized via a facile coprecipitation method and in situ polymerization followed by calcination under a nitrogen atmosphere. The obtained electrode provided a high specific capacity of 333.7 C g−1 and still retained 188.8 C g−1 when the current density increased by 40 times. Remarkably, it exhibited outstanding cycling stability with 82% retention of capacity after 10 000 cycles in an aqueous alkaline electrolyte, which benefited from the inner Ni–Co PBA quantum dots that provided a surrounding space and significantly accommodated the volume change during the repeated charge–discharge process, and the outer carbon layer that served as a protective barrier to hinder the Ni–Co PBA from dissolving into the electrolyte, thus realizing the durability of the electrode. Furthermore, an asymmetric alkaline battery device was assembled which achieved a maximum energy density of 33.2 W h kg−1 and a power density of 3.1 kW kg−1. Our work contributed to the development of PBA-based electrode materials with improved cycling stability as battery-type electrodes in aqueous electrolytes. [ABSTRACT FROM AUTHOR]

Bi2O3 is a theoretically high capacitive anode material; however, its low conductivity and deficient surface‐active sites lead to reduced practical capability compared to the theoretical one. Herein, a facile and environmentally benign strategy is developed to simultaneously tailor the morphology and create oxygen vacancies in Bi2O3 by adding trace water in a solvothermal procedure. Here trace water serves as an intermediary agent to change the growth mechanism of Bi2O3 and form a hierarchical structure with increased crystallinity. Electrochemical experiments reveal that the optimal tremella‐shaped Bi2O3 delivers a higher specific capacity, approximately reaching 65 % of the theoretical one. Such satisfactory electrochemical performance is due to the regulated tremella shape and the created oxygen vacancies, which can expose more electrochemical active‐sites and promote ion diffusion. Moreover, the massive oxygen vacancies and increased crystallinity are also beneficial for electron transfer, thus enhancing the capacity. Eventually, a Bi2O3‐6//AC asymmetric device is constructed and a superior energy density (40.8 Wh kg−1) is realized than the others Bi2O3‐based peers. This study paves a facile way for exploring advanced Bi2O3‐based alkaline battery anode materials through an environmentally benign method. [ABSTRACT FROM AUTHOR]

The nickel-iron (Ni-Fe) battery is a century-old technology that fell out of favor compared to modern batteries such as lead–acid and lithium-ion batteries. However, in the last decade, there has been a resurgence of interest because of its robustness and longevity, making it well-suited for niche applications, such as off-grid energy storage systems. Currently, extensive research is focused on addressing perennial issues such as iron passivation and hydrogen evolution reaction, which limit the battery's energy density, cyclability, and rate performance. Despite efforts to modify electrode composition and morphology, these issues persist, warranting a deeper look at the development story of Ni-Fe battery improvements. In this review, the fundamental reaction mechanisms are comprehensively examined to understand the cause of persisting issues. The design improvements for both the anode and cathode of Ni-Fe batteries are discussed and summarized to identify the promising approach and provide insights on future research directions. [ABSTRACT FROM AUTHOR]

The advent of wearable electronics has strongly stimulated advanced research into the exploration of flexible zinc−air batteries (ZABs) with high theoretical energy density, high inherent safety, and low cost. However, the half‐open battery structure and the high concentration of alkaline aqueous environment pose great challenges on the electrolyte retention capability and the zinc anode stability. Herein, a starch‐based superabsorbent hydrogel polymer electrolyte (SSHPE) with high ionic conductivity, electrolyte absorption and retention capabilities, strong alkaline resistance and high zinc anode stability has been designed and applied in ZABs. Experimental and calculational analyses probe into the root of the superiority of SSHPEs, confirming the significance of the carboxyl functional groups along their polymer chains. These features endow the as‐fabricated ZAB a long cycle life of 300 h, much longer than that with commonly used poly(vinyl alcohol)‐based electrolyte. [ABSTRACT FROM AUTHOR]

Portable and autonomous microdevices often require on-board power sources such as thin film microbatteries. Air microbatteries are an attractive power source for such devices due to their high specific energy density. One particularly appropriate air chemistry is based on Zn, due to the multiple microfabrication approaches compatible with Zn anode formation. We demonstrate fabrication approaches to realize Zn film anodes in different thickness regimes using microelectromechanical systems based fabrication techniques—evaporation, electrodeposition, and laser micromachining; and evaluate their relative performance as power sources in a primary battery configuration. These fabrication techniques enable films in thickness regimes ranging from the micron scale to hundreds of microns. The fabricated films have been characterized using scanning electron microscopy and energy dispersive x-ray spectroscopy, and were found to be dense and reasonably free from impurities. The electrochemical and discharge properties of the fabricated films were studied in an air battery configuration comprising a Zn anode-alkaline hydrogel electrolyte-metal catalyst stack, in which the anode had a surface area of 0.78 cm2. Evaporated Zn anodes (1–10 µ ms) yielded Zn utilizations of 96.5% and 82% at 10 and 1 mA discharge rates, respectively. The specific capacity of the evaporated Zn anodes was 791 mAh g−1 when discharged at 10 mA, close to the Zn theoretical specific capacity of 820 mAh g−1. Electrodeposited Zn anodes (10–100 µ ms) yielded utilizations of 90.2% and 75.6% at 10 and 1 mA discharge rates, respectively. Laser micromachined Zn anodes (250 µ ms) yielded Zn utilization of 90% when discharged at 10 mA. These fabrication techniques offer the potential to realize high energy density Zn anodes of different thickness ranges for thin film microbatteries, which can be tailored to microdevice-based applications of interest. [ABSTRACT FROM AUTHOR]

Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co‐free lithium ion batteries based on layered Mn oxides presently lack the longevity and stability of their Co‐containing counterparts. Here, a reduction in this performance gap is demonstrated via chemical doping, with Li1.1Ni0.35Mn0.54Al0.01O2 achieving an initial discharge capacity of 159 mAhg−1 at C/3 rate and a corresponding capacity retention of 94.3% after 150 cycles. The nanoscale origins of this improvement are subsequently explored through a combination of advanced diffraction, spectroscopy, and electron microscopy techniques, finding that optimized doping profiles lead to an improved structural and chemical compatibility between the two constituent sub‐phases that characterize the layered Mn oxide system, resulting in the formation of unobstructed lithium ion pathways between them. A structural stabilization effect of the host compound is also directly observed near the surface using aberration corrected scanning transmission electron microscopy and integrated differential phase contrast imaging. [ABSTRACT FROM AUTHOR]

Independent photo‐charging technologies based on aqueous zinc‐ion batteries (ZIBs) are promising candidates for next‐generation renewable energy systems. The conflict between light utilization and electrochemical performance in the planar electrode severely limits the availability of photo‐charging ZIBs. Herein, 3D light‐trapping structures (LTSs) are proposed and applied in a rigid VO2/C@SiCuOC electrode. A hybrid‐reflection effect driven by LTSs is employed to improve light‐harvesting efficiency. The suitable energy levels of VO2 and C ensure charge transport, while the rigid SiCuOC support meets the stability requirements. Such a 3D VO2/C@SiCuOC electrode exhibits a multiplying photo‐response current density of 42.2 µA cm−2 (≈400% of the plate) and delivers a higher energy density (0.19 mWh cm−2 at 0.51 mW cm−2). More importantly, in a realistic environment (dark for 16 h and light for 8 h), the photo‐charging ZIBs integrated into a roof exhibit an exciting open circuit voltage of 3.176 V (three in series) and supply electricity continuously. The high strength (over 9 MPa) of the photo‐charging ZIBs inherited from the 3D rigid electrode further enables its practical application. The enhanced performance of the photo‐charging ZIBs obtained from structural optimization provides unique inspiration for next‐generation clean energy harvest/storage systems. [ABSTRACT FROM AUTHOR]

Alkaline Bi//Zn batteries with superb safety, low cost, and high power density are promising candidates for large‐scale electrical energy storage. However, their developments are severely limited by the Bi‐based cathode as the unsatisfying capacity and cycle life. Herein, an innovative multistage cubic nanospheres Bi12SiO20 (MCS‐Bi12SiO20) is successfully synthesized by a simple calcination method, which shows excellent energy storage performances of superior specific capacity (294 mAh g−1 at 0.5 A g−1) and outstanding rate capability (134 mAh g−1 at 12 A g−1). When coupled with Zn anode a superior MCS‐Bi12SiO20//Zn is fabricated, which delivers a high energy density of 247.5 Wh kg−1 at the power density of 375 W kg−1. Additionally, the MCS‐Bi12SiO20//Zn battery shows excellent cycle life, which reserves more than 100 % of its original capacity after 5000 cycles. Such performance is higher than previously reported Bi//Zn battery and most other Zn batteries. This is the first example of using Bi12SiO20 as cathode for RAZBs, which may provide highly promising material towards better Bi//Zn battery. [ABSTRACT FROM AUTHOR]

Aqueous zinc–manganese batteries with low cost, reliable safety, and considerable energy density, show promise for grid‐scale storage. Their durable operation is highly dependent on the reversibility and stability of both electrode interfaces, which is limited by the different requirements of the interfaces of manganese‐based cathodes and zinc anodes. Here, a quasi‐decoupled solid–liquid hybrid electrolyte is proposed, which demonstrates good compatibility and high reversibility for both interfaces with different electrolyte environments, showing quasi‐decoupling characteristics. Such a hybrid electrolyte can endow the anode interface with abundant favorable nucleation sites for achieving uniform zinc platting/stripping, as well as limit the presence of free H2O molecules, to suppress side‐reactions. This electrolyte is also adapted to a reversible and stable MnO2/Mn2+ manganese deposition/dissolution reaction at the cathode interface by restricting OH−/H+ ion diffusion, preventing formation of irreversible electrochemically inert MnOOH. As a result, the quasi‐decoupled solid–liquid hybrid electrolyte enables Zn||Zn cycling for more than 500 h, and a specific capacity of a Zn||α‐MnO2 battery up to 348 mAh g−1 at 0.2 A g−1. It also allows 87% capacity retention after 500 cycles at 0.5 A g−1. This work provides a new insight into electrolyte design that focuses on the different requirements of differing electrode interfaces. [ABSTRACT FROM AUTHOR]

With the merits of low cost, environmental friendliness and rich resources, manganese dioxide is considered to be a promising cathode material for aqueous zinc-ion batteries (AZIBs). However, its low ion diffusion and structural instability greatly limit its practical application. Hence, we developed an ion pre-intercalation strategy based on a simple water bath method to grow in situ δ-MnO2 nanosheets on flexible carbon cloth substrate (MnO2), while pre-intercalated Na+ in the interlayer of δ-MnO2 nanosheets (Na-MnO2), which effectively enlarges the layer spacing and enhances the conductivity of Na-MnO2. The prepared Na-MnO2//Zn battery obtained a fairly high capacity of 251 mAh g−1 at a current density of 2 A g−1, a satisfactory cycle life (62.5% of its initial capacity after 500 cycles) and favorable rate capability (96 mAh g−1 at 8 A g−1). Furthermore, this study revealed that the pre-intercalation engineering of alkaline cations is an effective method to boost the properties of δ-MnO2 zinc storage and provides new insights into the construction of high energy density flexible electrodes. [ABSTRACT FROM AUTHOR]

In recent years, supercapacitors and alkaline Ni-Zn batteries have attracted increasing attention owing to the advantages of high energy density, excellent rate performance, low price, environmental protection and safety. In this study, a ZnCoNi-MOF precursor was prepared on nickel foam (NF) by the solvothermal method, and then a robust transition metal oxide ZnCo2O4-NiO nanosheet array material was formed by calcination. As a supercapacitor cathode material, the self-supported ZnCo2O4-NiO nanosheet array electrode exhibits a high mass-specific capacitance of 196.67 mA h g-1 (1573.66 F g-1) at a current density of 1 A g-1; even when the current density is increased by 20 times, the electrode still maintains 75.5% of the initial capacity. In addition, the electrode exhibits an excellent performance rate, and the retention rate can still maintain 69.6% of the initial capacity after 10 000 cycles, which indicates that the electrode material has excellent electrochemical performance and cycle stability. When a ZnCo2O4-NiO//Zn battery was assembled, the potential platform was impressively extended to 1.70 V. The ZnCo2O4-NiO//Zn battery delivers a high capacity of 191.67 mA h g-1 at 1 A g-1. After 6000 cycles at a high current density of 8 A g-1, the capacity retention rate is 63.33%, which is promising for constructing an alkaline Ni-Zn battery with a long life span. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐based batteries hold multiple advantages of eco‐friendliness, easy accessibility, high safety, easy fabrication, and fast kinetics, while their widespread applications have been greatly limited by the relatively narrow thermodynamically stable potential windows (i. e. 1.23 V) of water and the mismatched pH conditions between cathode and anode, which presents challenges regarding how to maximize the output voltage and the energy density. Recently, aqueous OH−/H+ dual‐ion Zn‐based batteries (OH−/H+‐DIZBs), where the Zn anode reacts with hydroxide ions (OH−) in alkaline electrolyte while hydrogen ions (H+) are involved in the cathode reaction in the acidic electrolyte, have been reported to be capable of broadening the working voltage and improving the energy density, which offers practical feasibility toward overcoming the above limitations. This Review thus takes this chance to investigate the recent progress on aqueous OH−/H+‐DIZBs. First, the concept and the history of such OH−/H+‐DIZBs are introduced, and then special emphasis is put on the working mechanisms, the progress of the development of new batteries, and how the electrolytes improve their performance. Finally, the challenges and opportunities in this field are discussed. [ABSTRACT FROM AUTHOR]

As an energy storage device, the aqueous alkaline battery holds great potential, particularly for applications requiring high energy density and high power density. Anode materials with excellent performance are indispensable to producing stable and high-energy aqueous rechargeable batteries. In this study, 3D-printed porous and planar substrates were employed as growth vehicles for Bi 2 O 3. As a result, rapid charge transfer and ion diffusion are successfully achieved by utilizing porous structure channels. A remarkable specific capacity of 2.63 mAh cm−2 is attained for the porous structure-based Bi 2 O 3 , which can attribute to the formed p-type homojunction between CuO/Cu 2 O and Bi 2 O 3. Additionally, the cycle stability of Bi 2 O 3 deposited on the porous structure substrate is enhanced dramatically due to this structure enables less bismuth-based salt ions, oxide, and hydroxide deposition. Consequently, the harmful accumulation of bismuth-based mixture deposition on the anode surface was prevented, resulting in the mitigation of electrode passivation. Besides, a favorable photoresponse rate is displayed for the porous structure Bi 2 O 3 anode, proving the practicable Cu&Bi 2 O 3 combination and the reasonable structural design. [ABSTRACT FROM AUTHOR]

In aluminum-air batteries, hydrogen precipitation corrosion is a difficult problem for aluminum anodes in alkaline electrolytes, which causes a decrease in the efficiency and shortens the service life of aluminum anodes. Under the condition of 4 mol·L-1 NaOH alkaline solution, the addition of trace Sb (0.04 wt%) to Al-Zn-0.5Sn-0.5Mn resulted in an increase of 88.64% in energy density and 74.03% in the specific capacity of the aluminum anode, and a constant current discharge at a current density of 10 mA·cm-2, with a discharge voltage as high as 1.43 V and the discharge process is stable, the anode efficiency reaches 90.90% and the energy density reaches 2526 Wh·kg-1. The improvement in the performance of the aluminum anode is mainly due to the precipitation of the AlSb phase, which activates the grain boundaries, improves the electrochemical activity of the aluminum anode, and forms Sb-containing membranes to inhibit the formation of surface passivation films. Efficient discharge in alkaline solution and long battery life. [ABSTRACT FROM AUTHOR]

Alkaline aqueous Zn/Co 3 O 4 batteries (AZCBs) have captured significant attention within the field of scalable grid energy storage due to their high output voltage (>1.8 V), superior safety profile, and low manufacturing cost. Nevertheless, the intrinsic Co 3 O 4 material experiences limitations in terms of low electronic conductivity and insufficient active sites, consequently constraining its electrochemical performance in AZCBs. To address this challenge, this investigation focuses on the use of phosphate ions functionalized Co 3 O 4 (referred to as PCO) material derived from cobalt-based metal-organic frameworks (Co-MOFs) as a cathode electrode in AZCBs. Both theory calculations and experimental verification illustrate that the functionalization with phosphate ion enhances the active sites for electrochemical redox reactions and increases the electrical conductivity of intrinsic Co 3 O 4. Consequently, a pouch cell configuration of PCO-2||Zn with the optimized PCO-2 sample as cathode exhibits a high capacity of 162.0 mAh g−1, a maximum energy density of 265.7 Wh kg−1, a maximum power density of 16.39 kW kg−1. Furthermore, excellent long-term stability is observed, with the capacity retention rate reaching 92.3 % over 5000 cycles at a high current density of 5 A g−1. Additionally, the constructed fibrous flexible solid-state device also demonstrates notable long-term stability, with a capacity retention of 96 % after 2000 cycles under a high current density of 10 mA cm−2, and performs well under different deformation statuses. This successful approach may hold potential for the exploration of other cathode materials, such as Mn or V-based compounds, which may exhibit high performance in aqueous zinc-based batteries. • Phosphate ions functionalized Co 3 O 4 cathode derived from Co-MOFs has been prepared. • Phosphate ions increase active sites and electrical conductivity of intrinsic Co 3 O 4. • A pouch cell of PCO-2||Zn maintains capacity retention of 92.3 % over 5000 cycles. • The effect of phosphating intrinsic Co 3 O 4 was simulated by theory calculation. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous alkaline zinc-based batteries (AZBs) have sparked widespread attention considering their cost-effectiveness, favorable safety profiles, and robust output voltage. Nonetheless, the advancement of AZBs is being constrained by the lack of suitable cathode materials that exhibit high energy storage capacity and great cycle stability. In this work, nickel-cobalt bimetallic selenides (NCS) were synthesized as cathodes for AZBs using a simple one-pot hydrothermal approach, which avoided traditional high-temperature heating procedures, effectively lowering preparation costs, and improving production safety. The optimized sample, NCS-3, presents an impressive capacity of 225.8 mAh g–1 at 1 A g–1 and a satisfactory rate capacity of 194.8 mAh g–1 at an elevated current density of 10 A g–1. In addition, the NCS-3 electrode also achieves long-cycle stability (only 1 % capacity fade after 2000 cycles) and almost 100 % Coulomb efficiency, indicating outstanding structural stability and reversibility. Notably, the NCS-3//Zn battery constructed shows a maximum energy density of 339.3 Wh kg–1, and a power density of 12.5 kW kg–1, highlighting its potential for energy storage applications. [Display omitted] • A one-pot hydrothermal approach is reported to nickel-cobalt bimetallic selenides (NCS). • The optimized NCS electrode presents a high capacity of 225.8 mAh g–1 at 1 A g–1. • The fabricated battery can deliver a maximum energy density of 339.3 Wh kg–1. • This work reports a nickel-cobalt bimetallic selenide as a cathode for AZBs with enhanced capacity and cycling stability. [ABSTRACT FROM AUTHOR]

• A dual additive electrolyte is proposed for dendrite-free alkaline Ni-Zn batteries. • High discharge areal capacity of 9.6 mAh cm−2 is achieved. • Cumulative discharge capacity in full cells can reach ∼4000 mAh cm−2. Though obvious advantages in terms of safety, cost, environmental compatibility and electrochemical performance (e.g, power and energy density), the commercial application of alkaline Ni-Zn batteries, a number of traditional aqueous batteries, is still under great restrictions owing to the poor durability (commonly less than 100 cycles). In this work, an effective electrolyte modification process using dual additives of hydroxy-rich carboxymethyl cellulose (CMC) that can inhibit hydrogen evolution reaction (HER) and suppress Zn dendrites, and benzyltrimethylammonium bromide (BTMAB) that can mitigate passivation and oxygen evolution reaction (OER) is developed. Meanwhile, our home made C coated ZnO (ZnO@C) microspheres were used as initial anode materials without the using of any other expensive composites. With a fixed areal charge capacity of 10 mAh cm−2, the flat type full cell matched with commercial Ni(OH) 2 cathode can deliver a high average discharge capacity of ∼9.6 mAh cm−2 (corresponding to an average CE of 96 %) for a long lifespan of over 390 cycles, which drops to 8.2 mAh cm−2 at 400th cycle accompanied by the appearance of a peak in the charge curve. The cumulative discharge capacity of a full cell can reach ∼4,000 mAh cm−2 in 420 cycles' cycling, much larger than that using commercial Zn/ZnO anode and the ZnO@C anode in unmodified or single additive modified electrolyte (less than 1,500 mAh cm−2). [ABSTRACT FROM AUTHOR]

[Display omitted] • Crystalline/amorphous Co 2 P 2 O 7 was prepared in situ on nickel foam through hydrothermal and CVD annealing process. • The CP-P-450//Zn battery achieves an extraordinary areal capacity of 2.49 mAh/cm2 at a current density of 5 mA/cm2. • The CP-P-450//Zn battery showed superior areal energy densities (4.16 mWh/cm2) and peak power densities (115.94 mW/cm2). • The cycling durability of CP-P-450//Zn battery reached to 96.6% after 4000 cycles. It is still a challenge to develop aqueous rechargeable Zn-based alkaline batteries with high energy density, power density and excellent stability. Herein, a crystalline/amorphous Co 2 P 2 O 7 self-supporting on the Ni foam is fabricated as a cathode material of aqueous Zn-based alkaline batteries. The unique crystalline/amorphous structure endows the electrode material with more exposed active sites, higher redox species coverage, larger electrochemical surface area (ECSA), smaller charge-transfer resistance, lower reaction energy barriers and faster electrochemical reaction kinetics process, which clarifies an explicit structure–property relationship simultaneously. As a result, the crystalline/amorphous Co 2 P 2 O 7 (CP-P-450) electrode assembled as CP-P-450//Zn battery achieves an extraordinary areal capacity of 2.49 mAh cm−2 at 5 mA cm−2, satisfactory rate performance, excellent cyclic durability (96.6 % retention after 4000 cycles) and impressive energy density (4.16 mAh cm−2) and peak power density (115.94 mW cm−2). The quasi-solid CP-P-450//Zn battery can drive a variety of electrical appliances working well even under abuse tests, demonstrating excellent safety and application potential. This study provides an effective strategy towards excellent comprehensive energy storage performance of aqueous Zn-based alkaline batteries through structuring the crystalline/amorphous phase in cathodes. [ABSTRACT FROM AUTHOR]

Metallic antimony (Sb) as alkaline metal battery anode material, being thoroughly researched for its high theoretical specific capacity, but there is still a huge expansion problem with repeated insertion/de-insertion., We reported a unique composite material that encapsulates Sb nanoparticles in hierarchical porous carbon skeletons (Sb@HPCs) in this work, to explore the effect of the hierarchical porous carbon structure on the electrochemical performance of the Sb@HPCs as potassium-ion batteries (KIBs) and lithium-ion batteries (LIBs) anode materials. The macropores could promote the penetration of electrolyte, thus reducing the internal impedance of the battery. The mesopores provide a short ion diffusion path and a large diffusion region, which plays a crucial role in facilitating rapid ionic migration in both KIBs and LIBs. The micropores in the electrode material contribute to a larger specific surface area, which provides more surface area for charge storage, thus enhancing the energy density of the material. Importantly, when the Sb@HPCs composite material is applied as anode material of KIBs, it exhibits an outstanding specific capacity of 360 mAh g−1 after 100 cycles at 100 mA g−1. In the LIBs, the specific capacity of the composite material is 595.2mAh g−1 after 100 cycles at a current density of 0.1 A g−1; even at a high current density of 1.0 A g−1, the specific capacity still maintains at 320.4 mAh g−1 after 800 cycles, indicating an excellent cycling stability. The development of hierarchical porous three-dimensional structure offers a practical solution to the capacity degradation issues of metal anode in KIBs/LIBs. [Display omitted] • The combination of pores with different pore sizes effectively improves the conductivity and cycling stability. [ABSTRACT FROM AUTHOR]

Alkaline aqueous batteries such as the Zn||Ni batteries have attracted substantial interests due to their merits of high energy density, high safety and low cost. However, the freeze of aqueous electrolyte and the poor cycling stability in alkaline condition have hindered their operation in subzero conditions. Herein, we construct a stable aqueous electrolyte with lowest freezing point down to −90 °C by adding dimethyl sulfoxide (DMSO) as alkaline tolerant antifreezing additive into 1 M KOH solution. Meanwhile, we find the DMSO can also retard Zn anode corrosion and prevent Zn dendrite formation in alkaline condition, which enables the Zn plating/stripping over 700 h cycle at 1 mA cm−2 and 0.5 mAh cm−2. The fabricated Zn||Ni battery can endure low working temperature even down to −60 °C and its dischage capacity retains 84.1 % at −40 °C, 60.6 % at −60 °C at 0.5 C. Meanwhile, it can maintain 600 cycles with a specific capacity retention of 86.5 % at −40 °C at 2 C. [ABSTRACT FROM AUTHOR]

An electrolytic Zn-MnO2 battery based on a deposition/dissolution mechanism has shown great prospects in energy storage applications, due to its low cost and high energy density. However, the multi-electron electrochemical reaction of the manganese-based cathode in this battery depends on the electrolyte acidity. Here, the reaction mechanism at the cathode side is investigated when electrolytes with different acidities are used. The results show that the Mn2+/MnO2 deposition/dissolution and the cation intercalation coexist in the cathode of the electrolytic Zn-MnO2 battery when the electrolyte has a pH > 0.4. The battery exhibits an unstable variation of coulombic efficiency. Upon the increase of the proton concentration in the electrolyte, the manganese-based cathode demonstrated a one-step deposition/dissolution mechanism, which benefits a high discharge voltage up to 2 V of the battery and a stable coulombic efficiency of above 90%. This work provides a useful electrolyte design for electrolytic Zn-MnO2 batteries. [ABSTRACT FROM AUTHOR]

Aqueous Zn-based batteries show great potential in large scale energy storage system due to their low-cost and high-safety merits. However, the practical application of Zn-based batteries is restricted by their inferior energy and power densities, which is resulted from the low output voltage and poor reaction kinetics of cathode materials. To address the above issues, we propose a decoupled aqueous Zn–Mn battery with high-rate and high-voltage by using oxygen functionalized carbon nanotubes (OCNTs) substrate. The functional interface can greatly improve the wettability of the electrode, promote the ion transport capability, and facilitate the rapid deposition/dissolution of MnO2/Mn2+. Consequently, the OCNTs/MnO2 electrode can deliver a high capacity of 9.2 mA h cm−2 and superior capacity retention of 86.6% at an ultrahigh current density of 200 mA cm−2. When coupled with Zn anode, the Zn//OCNTs/MnO2 decoupled full battery exhibits a high discharge plateau (∼2.45 V) and area specific capacity (1.96 mA h cm−2) at a current density of 2 mA cm−2. Moreover, the outstanding peak power density of 13.4 kW kg−1 and peak energy density of 564.4 W h kg−1 can be achieved for Zn//OCNTs/MnO2 battery (based on the mass of active material involved in the reaction on the positive and negative electrodes during charge and discharge), far beyond currently reported aqueous electrochemical energy storage devices. This work provides a train of thoughts for the development of high energy and power density aqueous batteries. [ABSTRACT FROM AUTHOR]

Electrically rechargeable zinc‐air batteries attract extensive research interests due to their potentially high energy density and low cost but suffer from chemical instability and poor electrochemical reversibility caused by the corrosive nature of the conventional alkaline electrolyte. Here we demonstrate a non‐alkaline zinc acetate electrolyte for electrically rechargeable zinc‐air batteries with long‐term operation stability (>600 hours) in ambient air without any special cell engineering. The unique battery chemistry with reversible formation/decomposition of zinc hydroxyacetate dihydrate is systematically revealed using diversified electrochemical and analytical techniques. Furthermore, the carbon‐based air cathode is modified towards a hydrophilic surface to increase the energy efficiency. This work provides new insight on effective electrolyte design to achieve long‐term operation zinc‐air batteries. [ABSTRACT FROM AUTHOR]

Primary alkaline batteries have been widely used in portable electronics due to their low cost and safety. The consumption and disposal of these batteries has prompted notable research on their recycling. Another approach to reducing alkaline battery disposal is to extend their lifetime by increasing their energy density. In this work, the energy density of an AA primary alkaline battery was maximized by determining the optimum amount of electrode materials through multiphysics modeling. An electrochemical model of the alkaline battery is developed in COMSOL Multiphysics® and validated with discharge curves (i.e., voltage vs. time) obtained under constant resistance loads. The electrode thicknesses are then optimized to maximize the energy density of the battery while maintaining its exterior dimensions. The sensitivity of the energy density with respect to the electrode porosities and interfacial areas is then analyzed. The electrochemical model was able to replicate the discharge curves obtained under a 250 mA constant current discharge. The energy density is maximized by decreasing the thickness of the zinc anode. However, this results in anode dissolution near the current collectors and could compromise the electrical continuity in the battery. Increasing the anode thickness prevents dissolution at the current collectors but increases unused mass in the battery. The results of this study can be used to develop longer-lasting alkaline batteries. Furthermore, the model can be improved by considering thermal effects or modified to aid the development of rechargeable alkaline batteries. [ABSTRACT FROM AUTHOR]

Aqueous alkaline batteries (AABs) with the merits of both high energy density and power density have emerged as one of the most promising candidates for the new generation of energy storage devices, while their practical applications are still limited by the lack of high-performance electrode materials, especially for the anode materials. Herein, metallic bismuth–bismuth oxide nanoparticles (Bi–Bi2O3), with numerous heterogeneous interfaces, are successfully anchored and uniformly distributed on reduced graphene oxide (rGO) sheets. When Bi–Bi2O3/rGO-20 electrode is used as the anode material for an AAB, it shows a high specific capacity of 288.0 mA h g−1 (1036.9 F g−1) at 1 A g−1 and good rate capability (74.7% of capacity retention ratio at 20 A g−1). Additionally, in order to match well with a Bi–Bi2O3/rGO-20 anode, CoVSx thin sheets decorated with Ni–Co layered double hydroxide sheets (NiCo-LDH) were successfully constructed via a facile multistep hydrothermal method and a subsequent electrodeposition process. The resulting cathode exhibits a high specific capacity of 306.0 mA h g−1 (2448 F g−1) at 1 A g−1. The assembled CoVSx@NiCo-LDH//Bi–Bi2O3/rGO-20 AAB delivers an outstanding energy density of 106.1 Wh kg−1 at a power density of 789.6 W kg−1. Besides, the as-synthesized Bi-based electrode is also used in aqueous Zn alkaline batteries to further extend its application and the assembled Bi–Bi2O3/rGO-20//Zn batteries possess an ultralong flat discharge plateau and exhibit a specific capacity of 250.6 mA h g−1 at 1 A g−1. The results demonstrate that the as-assembled AAB has huge potential for practical applications and provides an inspiration for the next-generation energy storage devices. [ABSTRACT FROM AUTHOR]

Highly active and stable cathodes are critical for aqueous Zn–organic batteries with high capacity, fast redox kinetics, and long life. We herein report para‐, meta‐, and ortho‐dinitrobenzene (p‐, m‐, and o‐DB) containing two successive two‐electron processes, as cathode materials to boost the battery performance. Theoretical and experimental studies reveal that nitro constitutional isomerism is key to zincophilic activity and redox kinetics. p‐DB hosted in carbon nanoflower harvests a high capacity of 402 mAh g−1 and a superior stability up to 25 000 cycles at 5 A g−1, giving a Zn–organic battery with a high energy density of 230 Wh kg−1. An anionic co‐insertion charge storage mechanism is proposed, entailing a two‐step (de)coordination of Zn(CF3SO3)+ with nitro oxygen. Besides, dinitrobenzene can be electrochemically optimized by side group regulation via implanting electron‐withdrawing motifs. This work opens a new window to design multielectron nitroaromatics for Zn–organic batteries. [ABSTRACT FROM AUTHOR]

Alkali metal–O2 batteries exhibit ultra-high theoretical energy density which is even on par with fossil energy and are expected to become the next generation energy storage devices. However, to maintain the advantages of high energy density of alkali metal–O2 batteries, the reversibility of alkali metal anodes with high capacity is of vital importance. But the alkali metal anode with high chemical activity often faces a variety of challenges, including various side reactions, dendrite formation and volume expansion. In this highlight, we focus on the challenges faced by alkali metal anodes in alkali metal–O2 batteries and introduce the latest strategies to effectively stabilize the metal anode. Future perspectives are pointed out, which are valuable for the further development of nonaqueous alkaline metal–O2 batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The feasibility of Cu-Doped Graphene Cu/N 2 OG as battery electrodes is systematically studied. • Cu/N 2 OG has the record-theoretical capacity of 3303.7 mAh/g among all current NIBs anode materials. • Cu/N 2 OG exhibits impressive theoretical capacities of 1651.8 mAh/g and 1263.2 mAh/g for LIBs and KIBs, respectively. • Cu/N 2 OG is a superior anode with good conductivity, high capacity, fast ion diffusion, and tiny lattice change. Anode materials are paramount in dictating the performance of ion batteries. Therefore, the judicious design of novel anode materials boasting superior capacity is crucial to further enhancing the energy density of ion batteries. This study employs first-principles computational methods to systematically investigate the performance of Cu-doped graphene 2D material (Cu/N 2 OG) as an Li-ion batteries (LIBs), Na-ion batteries (NIBs), or K-ion batteries (KIBs) anode. Simulation results indicate that the structural asymmetry introduced by Cu doping significantly increases the active sites of the material, enhancing its theoretical specific capacity for Li/Na/K. Notably, the sodium storage theoretical capacity of Cu/N 2 OG reaches an impressive 3303.7 mAh/g, surpassing the capacity of all currently employed NIBs anode materials. Furthermore, Cu/N 2 OG also boasts high theoretical capacities, yielding capacities of 1651.8 mAh/g for LIBs and 1263.2 mAh/g for KIBs, respectively. The material retains excellent conductivity both prior to and following the adsorption of Li, Na, and K. Furthermore, Cu/N 2 OG demonstrates a low diffusion barrier and minimal lattice changes (<1 %), suggesting its potential as a high-performance anode for LIBs/NIBs/KIBs. [ABSTRACT FROM AUTHOR]