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Non-flow aqueous zinc-bromine batteries without auxiliary components (e.g., pumps, pipes, storage tanks) and ion-selective membranes represent a cost-effective and promising technology for large-scale energy storage. Unfortunately, they generally suffer from serious diffusion and shuttle of polybromide (Br−, Br3−) due to the weak physical adsorption between soluble polybromide and host carbon materials, which results in low energy efficiency and poor cycling stability. Here, we develop a novel self-capture organic bromine material (1,1′-bis [3-(trimethylammonio)propyl]-4,4′-bipyridinium bromine, NVBr4) to successfully realize reversible solid complexation of bromide components for stable non-flow zinc-bromine battery applications. The quaternary ammonium groups (NV4+ ions) can effectively capture the soluble polybromide species based on strong chemical interaction and realize reversible solid complexation confined within the porous electrodes, which transforms the conventional “liquid–liquid” conversion of soluble bromide components into “liquid–solid” model and effectively suppresses the shuttle effect. Thereby, the developed non-flow zinc-bromide battery provides an outstanding voltage platform at 1.7 V with a notable specific capacity of 325 mAh g−1NVBr4 (1 A g−1), excellent rate capability (200 mAh g−1NVBr4 at 20 A g−1), outstanding energy density of 469.6 Wh kg−1 and super-stable cycle life (20,000 cycles with 100% Coulombic efficiency), which outperforms most of reported zinc-halogen batteries. Further mechanism analysis and DFT calculations demonstrate that the chemical interaction of quaternary ammonium groups and bromide species is the main reason for suppressing the shuttle effect. The developed strategy can be extended to other halogen batteries to obtain stable charge storage.

Abstract Aqueous Zn-I flow batteries utilizing low-cost porous membranes are promising candidates for high-power-density large-scale energy storage. However, capacity loss and low Coulombic efficiency resulting from polyiodide cross-over hinder the grid-level battery performance. Here, we develop colloidal chemistry for iodine-starch catholytes, endowing enlarged-sized active materials by strong chemisorption-induced colloidal aggregation. The size-sieving effect effectively suppresses polyiodide cross-over, enabling the utilization of porous membranes with high ionic conductivity. The developed flow battery achieves a high-power density of 42 mW cm−2 at 37.5 mA cm−2 with a Coulombic efficiency of over 98% and prolonged cycling for 200 cycles at 32.4 Ah L−1 posolyte (50% state of charge), even at 50 °C. Furthermore, the scaled-up flow battery module integrating with photovoltaic packs demonstrates practical renewable energy storage capabilities. Cost analysis reveals a 14.3 times reduction in the installed cost due to the applicability of cheap porous membranes, indicating its potential competitiveness for grid energy storage.

Abstract The high redox potential of Zn0/2+ leads to low voltage of Zn batteries and therefore low energy density, plaguing deployment of Zn batteries in many energy-demanding applications. Though employing high-voltage cathode like spinel LiNi0.5Mn1.5O4 can increase the voltages of Zn batteries, Zn2+ ions will be immobilized in LiNi0.5Mn1.5O4 once intercalated, resulting in irreversibility. Here, we design a polymer hetero-electrolyte consisting of an anode layer with Zn2+ ions as charge carriers and a cathode layer that blocks the Zn2+ ion shuttle, which allows separated Zn and Li reversibility. As such, the Zn‖LNMO cell exhibits up to 2.4 V discharge voltage and 450 stable cycles with high reversible capacity, which are also attained in a scale-up pouch cell. The pouch cell shows a low self-discharge after resting for 28 days. The designed electrolyte paves the way to develop high-voltage Zn batteries based on reversible lithiated cathodes.

Ammonia (NH3) is an ideal green fuel with high energy density and plays an indispensable role in fertilizer production. Electrochemical reduction of nitrate (NO3–), a toxic pollutant in groundwater, has shown promising as a viable approach to converting waste into valuable NH3 under ambient conditions, offering an alternative to the energy-intensive Haber-Bosch process. Due to their high efficiency, copper (Cu)-based materials have shown great potential as electrocatalysts for the NO3– reduction reaction (NO3–RR) to NH3. In this review, we provide a comprehensive summary of the fundamental principles underlying nitrate reduction over Cu-based electrocatalysts and discuss various strategies to enhance the performance of NO3– reduction, including facets, morphologies, size, surface functionalization, compositional engineering, and defect engineering. We also delve into the relationship between the electrocatalytic performance and structure characteristics of electrocatalysts and thoroughly examine the reaction mechanism involved in NO3–RR. Furthermore, we highlight the existing challenges and prospective paths forward in this area of study. This review offers valuable insights and guidance for the strategic design and optimization of Cu-based electrocatalysts for NO3–RR applications.

Abstract Most current research is devoted to electrochemical nitrate reduction reaction for ammonia synthesis under alkaline/neutral media while the investigation of nitrate reduction under acidic conditions is rarely reported. In this work, we demonstrate the potential of TiO2 nanosheet with intrinsically poor hydrogen-evolution activity for selective and rapid nitrate reduction to ammonia under acidic conditions. Hybridized with iron phthalocyanine, the resulting catalyst displays remarkably improved efficiency toward ammonia formation owing to the enhanced nitrate adsorption, suppressed hydrogen evolution and lowered energy barrier for the rate-determining step. Then, an alkaline-acid hybrid Zn-nitrate battery was developed with high open-circuit voltage of 1.99 V and power density of 91.4 mW cm–2. Further, the environmental sulfur recovery can be powered by above hybrid battery and the hydrazine-nitrate fuel cell can be developed for simultaneously hydrazine/nitrate conversion and electricity generation. This work demonstrates the attractive potential of acidic nitrate reduction for ammonia electrosynthesis and broadens the field of energy conversion.

Abstract Aqueous copper-based batteries have many favourable properties and have thus attracted considerable attention, but their application is limited by their low operating voltage originating from the high potential of copper negative electrode (0.34 V vs. standard hydrogen electrode). Herein, we propose a coordination strategy for reducing the intrinsic negative electrode redox potential in aqueous copper-based batteries and thus improving their operating voltage. This is achieved by establishing an appropriate coordination environment through the electrolyte tailoring via Cl− ions. When coordinated with chlorine, the intermediate Cu+ ions in aqueous electrolytes are successfully stabilized and the electrochemical process is decoupled into two separate redox reactions involving Cu2+/Cu+ and Cu+/Cu0; Cu+/Cu0 results in a redox potential approximately 0.3 V lower than that for Cu2+/Cu0. Compared to the coordination with water, the coordination with chlorine also results in higher copper utilization, more rapid redox kinetics, and superior cycle stability. An aqueous copper-chlorine battery, harnessing Cl−/Cl0 redox reaction at the positive electrode, is discovered to have a high discharge voltage of 1.3 V, and retains 77.4% of initial capacity after 10,000 cycles. This work may open up an avenue to boosting the voltage and energy of aqueous copper batteries.

Objective: We have developed a baroreceptor-inspired microneedle skin patch for pressure-controlled drug release. Impact Statement: This design is inspired by the skin baroreceptors, which are mechanosensitive elements of the peripheral nervous system. We adopt the finger touching to trigger the electric stimulation, ensuring a fast-response and user-friendly administration with potentially minimal off-target effects. Introduction: Chronic skin diseases bring about large, recurrent skin damage and often require convenient and timely transdermal treatment. Traditional methods lack spatiotemporal controllable dosage, leaving a risk of skin irritation or drug resistance issues. Methods: The patch consists of drug-containing microneedles and stretchable electrode array. The electrode array, integrated with the piezoconductive switch and flexible battery, provides a mild electric current only at the spot that is pressed. Drugs in microneedles will then flow along the current into the skin tissues. The stretchable feature also provides the mechanical robustness and electric stability of the device on large skin area. Results: This device delivers Cy3 dye in pig skin with spatiotemporally controlled dosage, showing ~8 times higher fluorescence intensity than the passive delivery. We also deliver insulin and observe the reduction of the blood glucose level in the mouse model upon pressing. Compared with passive delivery without pressing, the dosage of drugs released by the simulation is 2.83 times higher. Conclusion: This baroreceptor-inspired microneedle skin patch acts as a good example of the biomimicking microneedle device in the precise control of the drug release profile at the spatiotemporal resolution.

Abstract Zn‐ion batteries are regarded as the most promising batteries for next‐generation, large‐scale energy storage because of their low cost, high safety, and eco‐friendly nature. The use of aqueous electrolytes results in poor reversibility and leads to many challenges related to the Zn anode. Electrolyte additives can effectively address many such challenges, including dendrite growth and corrosion. This review provides a comprehensive introduction to the major challenges in and current strategies used for Zn anode protection. In particular, an in‐depth and fundamental understanding is provided of the various functions of electrolyte additives, including electrostatic shielding, adsorption, in situ solid electrolyte interphase formation, enhancing water stability, and surface texture regulation. Potential future research directions for electrolyte additives used in aqueous Zn‐ion batteries are also discussed.

Abstract Solid polymer electrolytes (SPEs) and hydrogel electrolytes were developed as electrolytes for zinc ion batteries (ZIBs). Hydrogels can retain water molecules and provide high ionic conductivities; however, they contain many free water molecules, inevitably causing side reactions on the zinc anode. SPEs can enhance the stability of anodes, but they typically possess low ionic conductivities and result in high impedance. Here, we develop a lean water hydrogel electrolyte, aiming to balance ion transfer, anode stability, electrochemical stability window and resistance. This hydrogel is equipped with a molecular lubrication mechanism to ensure fast ion transportation. Additionally, this design leads to a widened electrochemical stability window and highly reversible zinc plating/ stripping. The full cell shows excellent cycling stability and capacity retentions at high and low current rates, respectively. Moreover, superior adhesion ability can be achieved, meeting the needs of flexible devices.

Abstract Aqueous iron batteries are appealing candidates for large-scale energy storage due to their safety and low-cost aspects. However, the development of aqueous Fe batteries is hindered by their inadequate long-term cycling stability. Here, we propose the synthesis and application as positive electrode active material of cross-linked polyaniline (C-PANI). We use melamine as the crosslinker to improve the electronical conductivity and electrochemical stability of the C-PANI. Indeed, when the C-PANI is tested in combination with a Fe metal negative electrode and 1 M iron trifluoromethanesulfonate (Fe(TOF)2) electrolyte solution, the coin cell can deliver a specific capacity of about 110 mAh g−1 and an average discharge voltage of 0.55 V after 39,000 cycles at 25 A g−1 with a test temperature of 28 °C ± 1 °C. Furthermore, mechanistic studies suggest that Fe2+ ions are bonded to TOF− anions to form positively charged complexes Fe(TOF)+, which are stored with protons in the C-PANI electrode structures. Finally, we also demonstrate the use of C-PANI in combination with a polymeric hydrogel electrolyte to produce a flexible reflective electrochromic lab-scale iron battery prototype.

Abstract One of the major obstacles hindering the application of zinc metal batteries is the contradictory demands from the Zn metal anode and cathodes. At the anode side, water induces serious corrosion and dendrite growth, remarkably suppressing the reversibility of Zn plating/stripping. At the cathode side, water is essential because many cathode materials require both H+ and Zn2+ insertion/extraction to achieve a high capacity and long lifespan. Herein, an asymmetric design of inorganic solid-state electrolyte combined with hydrogel electrolyte is presented to simultaneously meet the as-mentioned contrary requirements. The inorganic solid-state electrolyte is toward the Zn anode to realize a dendrite-free and corrosion-free highly reversible Zn plating/stripping, and the hydrogel electrolyte enables consequent H+ and Zn2+ insertion/extraction at the cathode side for high performance. Therefore, there is no hydrogen and dendrite growth detected in cells with a super high-areal-capacity up to 10 mAh·cm−2 (Zn//Zn), ~5.5 mAh·cm−2 (Zn//MnO2) and ~7.2 mAh·cm−2 (Zn//V2O5). These Zn//MnO2 and Zn//V2O5 batteries show remarkable cycling stability over 1000 cycles with 92.4% and over 400 cycles with 90.5% initial capacity retained, respectively.

Cl-redox reactions cannot be fully exploited in batteries because of the Cl2 gas evolution. Here, reversible high-energy interhalogen reactions are demonstrated by using a iodine-based cathode in combination with a Zn anode and a Cl-containing aqueous electrolyte solution.

The negative electrode reversibility limits the lifespan of Zn metal batteries. Here, authors report an aqueous electrolyte with a reverse micelle structure that improves the reversibility of the Zn metal anode enabling the production of an ampere-hour-level pouch cell with five months lifetime.

Co–N–C is a promising oxygen electrochemical catalyst due to its high stability and good durability. However, due to the limited adsorption ability improvement for oxygen-containing intermediates, it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide. Herein, the adsorption of Co–N–C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory. The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant (MoC/Co–N–C) are engineered to successfully modulate the d band center of active Co–N–C sites, resulting in a remarkably enhanced electrocatalysis performance. The optimally performing MoC/Co–N–C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry, featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction (ORR) and low overpotential of 370 mV for the oxygen evolution reaction (OER) at 10 mA cm−2. The zinc air batteries with the MoC/Co–N–C catalyst demonstrate a large power density of 180 mW cm−2 and a long cycling lifespan (2000 cycles). The density functional theory calculations with Hubbard correction (DFT + U) reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with “single site double adsorption” mode.

Highlights The excellent performance of MoS2/PANI cathode is due to better conductivity and desolvation shielding. The self-charging zinc battery was successfully assembled that achieve deep self-discharge and long cycle life. The quasi solid state battery and battery module have excellent performance and practicability.

Highlights The strong interaction between Ti3C2Sx and FeN4 species induces the central metal Fe(II) in FeN4 species with intermediate spin state transferred to high spin state, in which the latter is favorable to initiate the reduction of oxygen. This strong interaction induces a remarkable Fe 3d electron delocalization with d band center upshift, boosting oxygen-containing groups adsorption on FeN4 species and oxygen reduction reaction kinetics. The resulting FeN4–Ti3C2S x with FeN4 moieties in high spin state exhibits high half-wave potential of 0.89 V vs. RHE and high limiting current density of 6.5 mA cm−2, enabling wearable zinc–air battery showing a good discharge performance with a maximum power density of 133.6 mW cm−2.

Because of their high safety, low cost, and high volumetric specific capacity, zinc-ion batteries (ZIBs) are considered promising next-generation energy storage devices, especially given their high potential for large-scale energy storage. Despite these advantages, many problems remain for ZIBs—such as Zn dendrite growth, hydrogen evolution, and Zn anode corrosion—which significantly reduce the coulomb efficiency and reversibility of the battery and limit its cycle lifespan, resulting in much uncertainty in terms of its practical applications. Numerous electrolyte additives have been proposed in recent years to solve the aforementioned problems. This review focuses on electrolyte additives and discusses the different substances employed as additives to overcome the problems by altering the Zn ^2+ solvation structure, creating a protective layer at the anode–electrolyte interface, and modulating the Zn ^2+ distribution to be even and Zn deposition to be uniform. On the basis of the review, the possible research strategies, future directions of electrolyte additive development, and the existing problems to be solved are also described.

Abstract The quest for advanced energy storage devices with cheaper, safer, more resource‐abundant storage has triggered intense research into zinc ion batteries (ZIBs). Among them, organic materials as cathode materials for ZIBs have attracted great interest due to their flexible structure designability, high theoretical capacity, environmental friendliness, and sustainability. Although numerous organic electrode materials have been studied and different redox mechanisms have been proposed in the past decade, their electrochemical performance still needs further improvement, and the mechanisms require further exploration. This paper provides a systematical overview of three types of organic materials (bipolar‐type conductive polymer, n‐type conjugated carbonyl compounds, and p‐type material) on the energy storage mechanisms and distinct characteristics. We then focus on discussing the design strategies to improve electrochemical performance. Furthermore, the challenges and future research directions are discussed to provide a foundation for further developing organic‐based ZIBs.

The emergence of new quantum degrees of freedom provides an opportunity for the development and breakthrough of performance bottlenecks in functional materials for modern applications. This article provides an overview of quantum functional materials, including magnetic materials, optical materials, and topological materials, based on electron transport, orbital angular momentum, and spin coupling degrees of freedom. Spin degrees of freedom mainly affect the applications of magnetic materials in storage and computing fields, while orbital angular momentum degrees of freedom demonstrate high-dimensional degrees of freedom in optical devices with potential breakthrough applications in areas such as optoelectronic detection and sensing. The unique bulk-surface separated electron transport properties of topological materials can be applied to topological insulators, topological superconductors, and other fields. The application prospects of quantum functional materials are very broad, and finding new degrees of freedom and quantum degrees of freedom in traditional materials is an important opportunity for advancing technological development and transformation. Further theoretical research and the development of high spatial and temporal resolution, in situ spectroscopic detection methods will help discover more quantum functional materials and promote their applications.

Abstract Among the promising batteries for electric vehicles, rechargeable Li‐air (O2) batteries (LABs) have risen keen interest due to their high energy density. However, safety issues of conventional nonaqueous electrolytes remain the bottleneck of practical implementation of LABs. Solid‐state electrolytes (SSEs) with non‐flammable and eco‐friendly properties are expected to alleviate their safety concerns, which have become a research focus in the research field of LABs. Herein, we present a systematic review on the progress of SSEs for rechargeable LABs, mainly focusing on the interfacial issues existing between the SSEs and electrodes. The discussion highlights the challenges and feasible strategies for designing suitable SSEs for LABs.

Summary: Oxygen redox electrocatalysis is the crucial electrode reaction among new-era energy sources. The prerequisite to rationally design an ideal electrocatalyst is accurately identifying the structure-activity relationship based on the so-called descriptors which link the catalytic performance with structural properties. However, the quick discovery of those descriptors remains challenging. In recent, the high-throughput computing and machine learning methods were identified to present great prospects for accelerating the screening of descriptors. That new research paradigm improves cognition in the way of oxygen evolution reaction/oxygen reduction reaction activity descriptor and reinforces the understanding of intrinsic physical and chemical features in the electrocatalytic process from a multiscale perspective. This review summarizes those new research paradigms for screening multiscale descriptors, especially from atomic scale to cluster mesoscale and bulk macroscale. The development of descriptors from traditional intermediate to eigen feature parameters has been addressed which provides guidance for the intelligent design of new energy materials.

Long-lasting zinc metal electrodes are crucial in developing commercial zinc-based batteries. Here, the authors investigate the different morphology evolution between the stripping and plating process and propose electrochemical protocols to prolong the lifespan of zinc anodes.

Secondary alkaline Zn-based batteries are limited in terms of cycle life. Here, the authors report a nanoporous Zn electrode that stabilizes the electrochemical transition between Zn and ZnO and improves the cycling performance of rechargeable alkaline zinc-based batteries.

Despite the remarkable ion-hosting capability of MXenes, their electrochemical performance is restricted to the ion shuttle barrier stemming from the capacious surface and the sluggish chemical activity of intrinsic transition metal layers. Herein, we construct a vertically aligned array of V2CTX flakes utilizing a carbon sphere template (V2CTX@CS), with the interlayer galleries outward facing the external electrolyte, to shorten the diffusion length and mitigate the ion shuttle barrier. Moreover, we leverage the high sensitivity of V2CTX flakes to the water–oxygen environment, fully activating the masked active sites of transition metal layers in an aqueous environment via continuous electrochemical scanning. Aqueous V2CTX@CS/Zn battery delivers a novel capacity enhancement over 42,000 cycles at 10 A g−1. After activation, the capacity reaches up to 409 mAh [Formula: see text] at 0.5 A g−1 and remains at 122 mAh [Formula: see text] at 18 A g−1. With a 0.95-V voltage plateau, the energy density of 330.4 Wh [Formula: see text] surpasses previous records of aqueous MXene electrodes.

The performances of rechargeable batteries are detrimentally affected by low temperatures (e.g., < 0 °C). Here, the authors report a few-layer Bi2Se3 material capable of improving battery cycling performances when operational temperatures are shifted from +25 °C to −20 °C.

Mechanical stability of flexible batteries is the guarantee for delivering stable performance. The interacting external and inner forces determine it.

Abstract As promising anodes for sodium-ion batteries, metal sulfides ubiquitously suffer from low-rate and high-plateau issues, greatly hindering their application in full-cells. Herein, exemplifying carbon nanotubes (CNTs)-stringed metal sulfides superstructure (CSC) assembled by nano-dispersed SnS2 and CoS2 phases, cocktail mediation effect similar to that of high-entropy materials is initially studied in ether-based electrolyte to solve the challenges. The high nano-dispersity of metal sulfides in CSC anode underlies the cocktail-like mediation effect, enabling the circumvention of intrinsic drawbacks of different metal sulfides. By utilizing ether-based electrolyte, the reversibility of metal sulfides is greatly improved, sustaining a long-life effectivity of cocktail-like mediation. As such, CSC effectively overcomes low-rate flaw of SnS2 and high-plateau demerit of CoS2, simultaneously realizes a high rate and a low plateau. In half-cells, CSC delivers an ultrahigh-rate capability of 327.6 mAh g−1 anode at 20 A g−1, far outperforming those of monometallic sulfides (SnS2, CoS2) and their mixtures. Compared with CoS2 phase and SnS2/CoS2 mixture, CSC shows remarkably lowered average charge voltage up to ca. 0.62 V. As-assembled CSC//Na1.5VPO4.8F0.7 full-cell shows a good rate capability (0.05 ~ 1.0 A g−1, 120.3 mAh g−1 electrode at 0.05 A g−1) and a high average discharge voltage up to 2.57 V, comparable to full-cells with alloy-type anodes. Kinetics analysis verifies that the cocktail-like mediation effect largely boosts the charge transfer and ionic diffusion in CSC, compared with single phase and mixed phases. Further mechanism study reveals that alternative and complementary electrochemical processes between nano-dispersed SnS2 and CoS2 phases are responsible for the lowered charge voltage of CSC. This electrolyte/structure-dependent cocktail-like mediation effect effectively enhances the practicability of metal sulfide anodes, which will boost the development of high-rate/-voltage sodium-ion full batteries.

The interactions between water molecules, electrode materials and anions are essential yet challenging for aqueous dual ion batteries. Here, the authors demonstrate the voltage manipulation of dual ion batteries through matching intercalation energy and solvation energy of different anions.

Development of negative electrode active materials alternative to Ca metal is essential for the progress of Ca-ion battery technology. Here, the authors disclose the proton-assisted Ca-ion storage behavior of a pentacenetetrone organic crystal reporting high-power cell performances.

Obtaining stable aqueous K-ion capacitors is still challenging due to the cathode materials tended to structurally collapse after long-term cycling during large-radius K-ion insertion/extraction. In this work, three different typical MXene electrodes, i.e., Nb2C, Ti2C, and Ti3C2 were individually investigated upon their electrochemical behaviors for potassium-ion (K-ion) storage. All these MXene materials exhibited pseudocapacitive-dominated behaviors, fast kinetics, and durable K-ion storage, delivering superior performance compared with other K-ion host materials. According to the experimental results, it could be ascribed to the intrinsically large interlayer distance for K-ion transport and the superb structural stability of MXene even subjected to long-term potassiation/depotassiation process.

Abstract Wearable sensing systems, as a spearhead of artificial intelligence, are playing increasingly important roles in many fields especially health monitoring. In order to achieve a better wearable experience, rationally integrating the two key components of sensing systems, that is, power supplies and sensors, has become a desperate requirement. However, limited by device designs and fabrication technologies, the current integrated sensing systems still face many great challenges, such as safety, miniaturization, mechanical stability, energy‐efficiency, sustainability, and comfortability. In this review, the key challenges and opportunities in the current development of integrated wearable sensing systems are summarized. By summarizing the typical configurations of diverse wearable power supplies, and recent advances concerning the integrated sensing systems driven by such power supplies, the representative integrated designs, and micro/nanofabrication technologies are highlighted. Lastly, some new directions and potential solutions aiming at the device‐level integration designs are outlooked.

Advanced scenario-adaptable infrared (IR) stealth materials are crucial for creating localized closed thermal environments. Low emissivity over the broadest possible band is expected, as is superior mechanical deformability. Herein, we report a series of Ti-based MXenes with naturally low emissivity as ideal IR shielding materials. Over a wavelength ranging from 2.5 to 25 μm, Ti3C2TX film delivers an average emissivity of 0.057 with the lowest point of 0.042. Such a low emissivity coupled with outstanding structural shaping capability is beyond the current grasp. The reflection-dominated mechanism is dissected. Also, some intriguing scenarios of IR stealth for wearable electronic devices and skin thermal control are demonstrated. This finding lights an encouraging path toward next-generation IR shielding by the expanding MXene family.

The rapid development of portable, wearable, and implantable electronic devices greatly stimulated the urgent demand for modern society for multifunctional and miniaturized electrochemical energy storage devices and their integrated microsystems. This article reviews material design and manufacturing technology in different micro-supercapacitors (MSCs) along with devices integrate to achieve the targets of their various applications in recent years. Finally, We also critically prospect the future development directions and challenges of MSCs.

Abstract While traditional three‐layer structure supercapacitors are under mechanical manipulations, the high‐stress region concentrates, inevitably causing persistent structural problems including interlayer slippage, crease formation, and delamination of the electrode–electrolyte interface. Toward this, an all‐polymeric, all‐elastic and non‐laminated supercapacitor with high mechanical reliability and excellent electrochemical performance is developed. Specifically, a polypyrrole electrode layer is in situ integrated into a silk fibroin‐based elastic supramolecular hydrogel film with extensive hydrogen and covalent bonds, where a non‐laminate device is realized with structural elasticity at the device level. The non‐laminate configuration can avoid slippage and delamination, while the elasticity can preclude crease formation. Furthermore, under more severe mechanical damage, the supercapacitors can restore the electrochemical performance through non‐autonomous self‐healing capabilities, where the supramolecular design of host–guest interactions in the hydrogel matrix results in a superior self‐healing efficiency approaching ≈95.8% even after 30 cutting/healing cycles. The all‐elastic supercapacitor delivers an areal capacitance of 0.37 F cm−2 and a volumetric energy density of 0.082 mW h cm−3, which can well‐maintain the specific capacitance even at −20 °C with over 85.2% retention after five cut/healing cycles.

Flexible energy storage devices have received tremendous attention with the rapid development of wearable electronics. Commercial lithium‐ion batteries are gradually reaching their theoretical capacity, which is still unable to meet the requirements of flexible electronics for high energy density. Lithium–sulfur batteries with a high theoretical capacity of 1675 mA h g−1 are regarded as the most promising next‐generation high‐energy‐density power source. Herein, the various recent efforts in the development of lithium–sulfur batteries based on carbonaceous and polymer materials are summarized, with an emphasis on flexible systems. Flexible lithium–sulfur batteries based on carbonaceous materials such as carbon nanotubes, graphene, and carbonized polymer or biomass, polymers, and solid‐state electrolytes are reviewed. Finally, the challenges and further improvements of lithium–sulfur batteries are summarized and prospected.

Zn metal batteries are promising for large-scale energy storage systems because of their extremely intrinsic safety and low cost. However, parasitic side reactions such as hydrogen evolution, Zn corrosion, and flourished dendrite growth behavior impede their practical implementation. Notably, electrode/electrolyte interface plays a critical role in regulating Zn deposition and improving the cyclic lifespan of rechargeable Zn metal batteries. Here, the fundamentals of Zn electrode/electrolyte interface and the related issues are discussed. Thereafter, competent strategies including artificial protective layers, electrolyte optimization, structural engineering to fulfill a stable working Zn metal anode are presented. Subsequently, progressive characterization techniques reveal interfacial chemistries and morphological evolution of Zn metal anodes are outlined. Finally, the significantly perspective to guide and promote the developed of Zn batteries are proposed. This review will serve to further advance the development of interfacial engineering for Zn metal anodes.

Abstract Aqueous rechargeable metal‐ion batteries (ARMBs) represent one of the current research frontiers due to their low cost, high safety, and other unique features. Evolving to a practically useful device, the ARMBs must be adaptable to various ambient, especially the cold weather. While much effort has been made on organic electrolyte batteries operating at low temperatures, the study on low‐temperature ARMBs is still in its infancy. The challenge mainly comes from water freezing at subzero temperatures, resulting in dramatically retarded kinetics. Here, the freezing behavior of water and its effects on subzero performances of ARMBs are first discussed. Then all strategies used to enhance subzero temperature performances of ARMBs by associating them with battery kinetics are summarized. The subzero temperature performances of ARMBs and organic electrolyte batteries are compared. The final section presents potential directions for further improvements and future perspectives of this thriving field.

Abstract Rechargeable Zn‐based batteries (RZBs) have attracted much attention and been regarded as one of the most promising candidates for next‐generation energy storage featured with high safety, low costs, environmental friendliness, and satisfactory energy density. The aqueous electrolyte system exhibits great potential to power the future wearable electronics. Apart from the achievements of high capacity cathode and stable electrolyte, the anode suffers from problems of dendrite growth, hydrogen evolution, and passivation with limited attention. The dendrite formation strongly restricts the battery lifespan. Therefore, strategies focused on dendrite suppression are carefully categorized and summarized in this review, including crystallographic orientation manipulation, electric field control, ion flux regulation, and mechanical shield. Each strategy and the detailed approaches are critically dissected. Finally, remaining challenges are emphasized in this review, expecting to supply further research with potential directions to fulfill the high performance of the Zn anodes.

In the past decade, MXenes family have undergone considerable development and have been widely investigated in various research fields, relying on their excellent physicochemical properties. Benefiting from the increasingly versatile preparation methods and the continued discovery of new members, their large-scale application has already been underway, with energy storage fields including supercapacitors and batteries leading. The synthesis methods and processing environment of MXenes, which are closely strictly to the microstructure, surface chemistry, and electronic properties, have attracted great attention. In this review, we review the phylogeny of MXenes materials in recent years, mainly focusing on the synthesis process and environmental stability.

Abstract Inspired by the sophisticated artificial leather garment industry and toward enhancing wearability of energy storage devices, we demonstrate a polyurethane artificial leather supercapacitor with large sheet electrodes embedded in the leather layer simultaneously working as a polyelectrolyte. This design totally reserves textiles underneath and thus addresses the well-known challenge of wearing comfortability. It provides a revolutionary configuration of wearable supercapacitors: the artificial leather on garment is also a supercapacitor. Unlike the polyvinyl alcohol-based acidic electrolytes, which are widely used, sodium chloride is used to modify the intrinsically fluorescent polyurethane leather for ionic transportation, which has no harm to human. The fluorescent leather supercapacitor is easily transferrable from any arbitrary substrates to form various patterns, enabling multifunctionalities of practical wearability, fashion, and energy storage.

Beyond the traditional focus on improvements in mechanical, electronic and absorption properties, controllability, actuation, and dynamic response of monoliths have received increasing attentions for practical applications. However, most of them could only realize simple response to constant conditions (e.g. a stationary magnetic field) while carrying out humdrum motions. By controlling distribution of metal organic framework obtained carbon-enriched Fe3O4 nanoparticles in self-assembly reduced graphene oxide (RGO) monoliths, we could achieve two distinctive RGO–Fe3O4 stirrers that could dynamically respond to the rapidly changing magnetic field while executing designed movements precisely: rotating with lying down posture or standing straight posture. These stirrers can not only be applied in environmental remediation (e.g. suction skimmer), but also be recycled as electrode active materials for supercapacitors after fulfilling their destiny, realizing transformation of trash to treasure, which will inspire other dynamically responsive monoliths for various applications.

Intrinsic short hole diffusion length is a well-known problem for α-Fe2O3 as a visible-light photocatalytic material. In this paper, a nanodisk morphology was designed to remarkably enhance separation of electron-hole pairs of α-Fe2O3. As expected, α-Fe2O3 nanodisks presented superior photocatalytic activity toward methylene blue degradation: more than 90% of the dye could be photodegraded within 30 min in comparison with a degradation efficiency of 50% for conventional Fe2O3 powder. The unique multilayer structure is thought to play a key role in the remarkably improved photocatalytic performance. Further experiments involving mechanism investigations revealed that instead of high surface area, ·OH plays a crucial role in methylene blue degradation and that O·2− may also contribute effectively to the degradation process. This paper demonstrates a facile and energy-saving route to fabricating homogenous α-Fe2O3 nanodisks with superior photocatalytic activity that is suitable for the treatment of contaminated water and that meets the requirement of mass production.

The fine regulation of catalysts by the atomic-level removal of inactive atoms can promote the active site exposure for performance enhancement, whereas suffering from the difficulty in controllably removing atoms using current micro/nano-scale material fabrication technologies. Here, we developed a surface atom knockout method to promote the active site exposure in an alloy catalyst. Taking Cu3Pd alloy as an example, it refers to assemble a battery using Cu3Pd and Zn as cathode and anode, the charge process of which proceeds at about 1.1 V, equal to the theoretical potential difference between Cu2+/Cu and Zn2+/Zn, suggesting the electricity-driven dissolution of Cu atoms. The precise knockout of Cu atoms is confirmed by the linear relationship between the amount of the removed Cu atoms and the battery cumulative specific capacity, which is attributed to the inherent atom-electron-capacity correspondence. We observed the surface atom knockout process at different stages and studied the evolution of the chemical environment. The alloy catalyst achieves a higher current density for oxygen reduction reaction compared to the original alloy and Pt/C. This work provides an atomic fabrication method for material synthesis and regulation toward the wide applications in catalysis, energy, and others. [ABSTRACT FROM AUTHOR]