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A SnP3 anode material with a theoretical volumetric capacity of 6890 mAh cm−3 is investigated for Na‐ion batteries. The SnP3/C can deliver a reversible capacity of 810 mAh g−1 at a current density of 150 mA g−1 for 150 cycles. The superior performance is attributed to the strong bonding interaction of P and Sn after desodiation. [ABSTRACT FROM AUTHOR]

A rechargeable hybrid Mg2+/Li+ battery is designed by coupling a dendrite‐free magnesium anode with an electrolyte‐compatible cathode in a mixed Mg2+/Li+ electrolyte. Due to the highly reversible lithiation/delithiation of the cathode and Mg deposition/dissolution in the electrolyte, the battery demonstrates the best overall performance among reported magnesium‐ion batteries and mixed‐ion batteries in terms of cycling stability, specific capacity, specific energy, and rate capability. [ABSTRACT FROM AUTHOR]

The LiFePO4/FePO4 phase transition process is remarkable in terms of its excellent reversibility, making this redox system extremely promising for high rate lithium storage. The recent observation of ordering effects (Li0.5FePO4) during the phase transition challenges the traditional two phase models. In this work, the phenomenon of staging for LiFePO4 for different sizes (70 nm and 50 nm) by high resolution aberration corrected annular bright electron microscopy is detected, investigated, and discussed along with previous results on larger crystals. In the small crystals, staging is found throughout with a decrease of order from center to the surface. For the larger crystal, a staging phase occurs constituting the interfacial zone (width around 15 nm) between LiFePO4 and FePO4. A comparison is made to recent experiments on even larger crystals showing such an interphase of smaller extent (around 2 nm). Thus it appears that these zones narrow with increasing size. These findings are discussed in the light of phase transition thermodynamics and kinetics. In particular, the possibility is discussed that the staging interphase may constitute a low energy solution to the LiFePO4/FePO4 contact. [ABSTRACT FROM AUTHOR]

We investigate the effects of carbon coating, with and without nitrogen-dopants, on the electrochemical performance of a promising anode material Li4Ti5O12(LTO) in lithium ion battery applications. The comparative experimental results show that LTO samples coated with nitrogen-doped carbon derived from pyridine and an ionic liquid exhibit significant improvements in rate capability and cycling performance compared with a LTO sample coated by carbon derived from toluene and the pristine LTO sample. For the first time, we construct an atomistic model for the interface between the lithium transition metal oxide and carbon coating layers. Our first-principles calculations based on density functional theory reveal that at this interface there is strong binding between the graphene coating layer and the Ti-terminated LTO surface, which significantly reduces the chemical activity of LTO surfaces and stabilizes the electrode/electrolyte interface, providing a clue to solve the swelling problem for LTO-based batteries. More importantly, electron transfer from the LTO surface to graphene greatly improves the electric conductivity of the interface. Nitrogen-dopants in graphene coatings further increase the interfacial stability and electric conductivity, which is beneficial to the electrochemical performance in energy storage applications. [ABSTRACT FROM AUTHOR]

The LiFePO4/FePO4 phase transition process is remarkable in terms of its excellent reversibility, making this redox system extremely promising for high rate lithium storage. The recent observation of ordering effects (Li0.5FePO4) during the phase transition challenges the traditional two phase models. In this work, the phenomenon of staging for LiFePO4 for different sizes (70 nm and 50 nm) by high resolution aberration corrected annular bright electron microscopy is detected, investigated, and discussed along with previous results on larger crystals. In the small crystals, staging is found throughout with a decrease of order from center to the surface. For the larger crystal, a staging phase occurs constituting the interfacial zone (width around 15 nm) between LiFePO4 and FePO4. A comparison is made to recent experiments on even larger crystals showing such an interphase of smaller extent (around 2 nm). Thus it appears that these zones narrow with increasing size. These findings are discussed in the light of phase transition thermodynamics and kinetics. In particular, the possibility is discussed that the staging interphase may constitute a low energy solution to the LiFePO4/FePO4 contact. [ABSTRACT FROM AUTHOR]

The solid electrolyte interphase (SEI) plays a crucial role in extending the life of aqueous batteries. The traditional anion-derived SEI formation in aqueous electrolytes highly depends on high-concentrated organic fluorinating salts, resulting in low forming efficiency and long-term consumption. In response, this study proposes a bifunctional fluorocarbon electrode additive (BFEA) that enables electrochemical pre-reduction instead of TFSI anion to form the LiF-rich SEI and in situ produce conductive graphite inside the anode before the lithiation. The BFEA lowers the salt dependence of aqueous electrolytes, enabling the inorganic LiCl electrolyte to work first, but also successfully achieves a high SEI formation efficiency in the relatively low 10 m LiTFSI without mass transfer concerns, suppressing the parasitic hydrogen evolution from 11.24 to 4.35 nmol min -1 . Besides, BFEA strengthens the intrinsic superiority of Li storage reaction by lowering battery polarization resulting from the in situ production of graphite, promoting charge transfer of electrode kinetics. Compared with the control group, the demonstrated Ah-level pouch cell employing BFEA exhibits better cycle stability above 300 cycles with higher capacity retention of 78.2% and the lower decay of the round-trip efficiency (△ RTE = 2%), benefiting for maintaining the high efficiency and reducing heat accumulation in large-scale electric energy storage., (© 2024 Wiley‐VCH GmbH.)

Aqueous batteries are attractive due to their high safety and fast reaction kinetics, but the narrow electrochemical stability window of H 2 O limits their applications. It is a big challenge to broaden the electrochemical operation window of aqueous electrolytes while retaining fast reaction kinetics. Here, a new organic aqueous mixture electrolyte of manipulatable (3D) molecular microheterogeneity with H 2 O-rich and H 2 O-poor domains is demonstrated. H 2 O-poor domains molecularly surround the reformed microclusters of H 2 O molecules through interfacial H-bonds, which thus not only inhibit the long-range transfer of H 2 O but also allow fast and consecutive Li + transport. This new design enables low-voltage anodes reversibly cycling with aqueous-based electrolytes and high ionic conductivity of 4.5 mS cm -1 . LiMn 2 O 4 ||Li 4 Ti 5 O 12 full cells demonstrate excellent cycling stability over 1000 cycles under various C rates and a low temperature of -20 °C. 1 Ah pouch cell delivers a high energy density of 79.3 Wh kg -1 and high Coulombic efficiency of 99.4% at 1 C over 200 cycles. This work provides new insights into the design of electrolytes based on the molecular microheterogeneity for rechargeable batteries., (© 2024 Wiley‐VCH GmbH.)

Electrochemical-mechanical coupling poses enormous challenges to the interfacial and structural stability but create new opportunities to design innovative all-solid-state batteries from scratch. Relying on the solid-solid constraint in the space-limited domain structure, we propose to exploit the lithiation-induced stress to drive the active materials creep, thereby improving the structural integrity. For demonstration, we fabricate the creep-type all-solid-state cathode using creepable Se material and an all-in-one rigid ionic/electronic conducting Mo6Se8 framework. As indicated by the in-situ experiment and numerical simulation, this cathode presents unique capabilities in improving interparticle contact and avoiding particle fracture, leading to its superior electrochemical performance, including a superior long-cycle life of more than 3000 cycles at 0.5 C and a high volumetric energy density of 2460 Wh/L at the cathode level. We believe this innovative strategy to utilize mechanics to boost the electrochemical performance could shed light on the future design of all-solid-state batteries for practical applications., (© 2024. The Author(s).)

Aluminum current collectors are widely used in nonaqueous batteries owing to their cost-effectiveness, lightweightness, and ease of fabrication. However, they are excluded from aqueous batteries due to their severe corrosion in aqueous solutions. Here, we propose hydrolyzation-type anodic additives to form a robust passivation layer to suppress corrosion. These additives dramatically lower the corrosion current density of aluminum by nearly three orders of magnitude to ~10 -6 A cm -2 . In addition, realizing that electrochemical corrosion accompanies anode prelithiation, we propose a prototype of self-prolonging aqueous Li-ion batteries (Al ||LiMn 2 O 4  ||TiO 2 ), whose capacity retention rises from 49.5% to 70.1% after 200 cycles. A sacrificial aluminum electrode where electrochemical corrosion is utilized is introduced as an electron supplement to prolong the cycling life of aqueous batteries. Our work addresses the short-life issue of aqueous batteries resulting from the corrosion of the current collector and lithium loss from side reactions., (© 2024. The Author(s).)

Fluoro-substitution solvents have achieved great success in electrolyte engineering for high-energy lithium metal batteries, which, however, is beset by low solvating power, thermal and chemical instability, and possible battery swelling. Instead, we herein introduce cyanogen as the electron-withdrawing group to enhance the oxidative stability of ether solvents, in which cyanogen and ether oxygen form the chelating structure with Li + not notably undermining the solvating power. Cyano-group strongly bonds with transition metals (TMs) of NCM811 cathode to attenuate the catalytic reactivity of TMs toward bulk electrolytes. Besides, a stable and uniform cathode-electrolyte interphase (CEI) inhibits the violent oxidation decomposition of electrolytes and guarantees the structural integrity of the NCM811 cathode. Also, a N-containing and LiF-rich solid-electrolyte interphase (SEI) in our electrolyte facilitates fast Li + migration and dense Li deposition. Accordingly, our electrolyte enables a stable cycle of Li metal anode with Coulombic efficiency of 98.4% within 100 cycles. 81.8% capacity of 4.3 V NCM811 cathode remains after 200 cycles. Anode-free pouch cells with a capacity of 125 mAh maintain 76% capacity after 100 cycles, corresponding to an energy density of 397.5 Wh kg -1 ., Competing Interests: Competing interests statement:The authors declare no competing interest.

Solid electrolyte interphase (SEI) makes the electrochemical window of aqueous electrolytes beyond the thermodynamics limitation of water. However, achieving the energetic and robust SEI is more challenging in aqueous electrolytes because the low SEI formation efficiency (SFE) only contributed from anion-reduced products, and the low SEI formation quality (SFQ) negatively impacted by the hydrogen evolution, resulting in a high Li loss to compensate for SEI formation. Herein, we propose a highly efficient strategy to construct Spatially-Temporally Synchronized (STS) robust SEI by the involvement of synergistic chemical precipitation-electrochemical reduction. In this case, a robust Li 3 PO 4 -rich SEI enables intelligent inherent growth at the active site of the hydrogen by the chemical capture of the OH - stemmed from the HER to trigger the ionization balance of dihydrogen phosphate (H 2 PO 4 - ) shift to insoluble solid Li 3 PO 4 . It is worth highlighting that the Li 3 PO 4 formation does not extra-consume lithium derived from the cathode but makes good use of the product of HER (OH - ), prompting the SEI to achieve 100 % SFE and pushing the HER potential into -1.8 V vs. Ag/AgCl. This energetic and robust SEI offers a new way to achieve anion/concentration-independent interfacial chemistry for the aqueous batteries., (© 2023 Wiley-VCH GmbH.)

Aggressive chemistry involving Li metal anode (LMA) and high-voltage LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NCM811) cathode is deemed as a pragmatic approach to pursue the desperate 400 Wh kg -1 . Yet, their implementation is plagued by low Coulombic efficiency and inferior cycling stability. Herein, we propose an optimally fluorinated linear carboxylic ester (ethyl 3,3,3-trifluoropropanoate, FEP) paired with weakly solvating fluoroethylene carbonate and dissociated lithium salts (LiBF 4 and LiDFOB) to prepare a weakly solvating and dissociated electrolyte. An anion-enrichment interface prompts more anions' decomposition in the inner Helmholtz plane and higher reduction potential of anions. Consequently, the anion-derived interface chemistry contributes to the compact and columnar-structure Li deposits with a high CE of 98.7% and stable cycling of 4.6 V NCM811 and LiCoO 2 cathode. Accordingly, industrial anode-free pouch cells under harsh testing conditions deliver a high energy of 442.5 Wh kg -1 with 80% capacity retention after 100 cycles., (© 2023. The Author(s).)

Poly(ethylene oxide)-based solid-state electrolytes are widely considered promising candidates for the next generation of lithium and sodium metal batteries. However, several challenges, including low oxidation resistance and low cation transference number, hinder poly(ethylene oxide)-based electrolytes for broad applications. To circumvent these issues, here, we propose the design, synthesis and application of a fluoropolymer, i.e., poly(2,2,2-trifluoroethyl methacrylate). This polymer, when introduced into a poly(ethylene oxide)-based solid electrolyte, improves the electrochemical window stability and transference number. Via multiple physicochemical and theoretical characterizations, we identify the presence of tailored supramolecular bonds and peculiar morphological structures as the main factors responsible for the improved electrochemical performances. The polymeric solid electrolyte is also investigated in full lithium and sodium metal lab-scale cells. Interestingly, when tested in a single-layer pouch cell configuration in combination with a Li metal negative electrode and a LiMn 0.6 Fe 0.4 PO 4 -based positive electrode, the polymeric solid-state electrolyte enables 200 cycles at 42 mA·g -1 and 70 °C with a stable discharge capacity of approximately 2.5 mAh when an external pressure of 0.28 MPa is applied., (© 2022. The Author(s).)

Super-concentrated water-in-salt electrolytes make high-voltage aqueous batteries possible, but at the expense of high cost and several adverse effects, including high viscosity, low conductivity and slow kinetics. Here, we observe a concentration-dependent association between CO 2 and TFSI anions in water that reaches maximum strength at 5 mol kg -1 LiTFSI. This TFSI-CO 2 complex and its reduction chemistry allow us to decouple the interphasial responsibility of an aqueous electrolyte from its bulk properties, hence making high-voltage aqueous Li-ion batteries practical in dilute salt-in-water electrolytes. The CO 2 /salt-in-water electrolyte not only inherits the wide electrochemical stability window and non-flammability from water-in-salt electrolytes but also successfully circumvents the numerous disadvantages induced by excessive salt. This work represents a deviation from the water-in-salt pathway that not only benefits the development of practical aqueous batteries, but also highlights how the complex interactions between electrolyte components can be used to manipulate interphasial chemistry., (© 2021. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Owing to its unique structure, Chevrel phase (CP) is a promising candidate for applications in rechargeable multivalent (Mg and Al) batteries. However, its wide applications are severely limited by time-consuming and complex synthesis processes, accompanied by uncontrollable growth and large particle sizes, which will magnify the charge trapping effect and lower the electrochemical performance. Here, an iodine vapor transport reaction (IVT) is proposed to obtain large-scale and highly pure Mo 6 S 8 nanosheets, in which iodine helps to regulate the growth kinetics and induce the preferential growth of Mo 6 S 8 , as a typical three-dimensional material, to form nanosheets. When applied in rechargeable multivalent (Mg and Al) batteries, Mo 6 S 8 nanosheets show very fast kinetics owing to the short diffusion distance, thereby exhibiting lower polarization, higher capacities, and better low-temperature performance (up to -40 °C) compared to that of microparticles obtained via the conventional method. It is anticipated that Mo 6 S 8 nanosheets would boost the application of Chevrel phase, especially in areas of energy storage and catalysis, and the IVT reaction would be generalized to a wide range of inorganic compound nanosheets.

Prussian blue analogues (PBAs) are considered to be ideal multivalent cation host materials due to their unique open-framework structure. In aqueous solution, however, the PBAs' cathodes have a low reversible capacity limited by the single electrochemical group Fe(CN) 6 3- and high crystal water content. They also suffer from fast cycle fading, resulting from significant oxygen/hydrogen evolution and cathode dissolution. In this work, a high-capacity PBA-type FeFe(CN) 6 cathode with double transition metal redox sites is successfully demonstrated in 5 m Al(CF 3 SO 3 ) 3 Water-in-Salt electrolyte (Al-WISE). Due to Al-WISE having a wide electrochemical window (2.65 V) and low dissolution of the cathode, our PBA cathode exhibits a high discharge capacity of 116 mAh/g and the superior cycle stability >100 cycles with capacity fading of 0.39% per cycle.

A new super-concentrated aqueous electrolyte is proposed by introducing a second lithium salt. The resultant ultra-high concentration of 28 m led to more effective formation of a protective interphase on the anode along with further suppression of water activities at both anode and cathode surfaces. The improved electrochemical stability allows the use of TiO2 as the anode material, and a 2.5 V aqueous Li-ion cell based on LiMn2 O4 and carbon-coated TiO2 delivered the unprecedented energy density of 100 Wh kg(-1) for rechargeable aqueous Li-ion cells, along with excellent cycling stability and high coulombic efficiency. It has been demonstrated that the introduction of a second salts into the "water-in-salt" electrolyte further pushed the energy densities of aqueous Li-ion cells closer to those of the state-of-the-art Li-ion batteries., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)