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Rechargeable magnesium batteries could provide future energy storage systems with high energy density. One remaining challenge is the development of electrolytes compatible with the negative Mg electrode, enabling uniform plating and stripping with high Coulombic efficiencies. Often improvements are hindered by a lack of fundamental understanding of processes occurring during cycling, as well as t
The practical application of aqueous rechargeable batteries faces several challenges due to the limited stability window of electrolytes and parasitic side reactions, such as corrosion, passivation, gas evolution, and co-intercalations. The solid electrolyte interphase (SEI) formed at the electrode/electrolyte interface plays a critical role in determining interfacial properties and battery perfor
Battery cell assembly and testing in conventional battery research is acknowledged to be heavily time-consuming and often suffers from large cell-to-cell variations. Manual battery cell assembly and electrolyte formulations are prone to introducing errors which confound optimization strategies and upscaling. Herein we present ODACell, an automated electrolyte formulation and battery assembly setup
The urgent need for improving the energy density of aqueous lithium ion batteries (ALIBs) can be addressed by the implementation of advanced electrode materials and electrolytes. The utilization of layered oxide cathodes, particularly Li[NixCoyMnz]O2 (NCM) materials, is an effective strategy, as they can offer high specific capacities in an appropriate voltage range. However, due to the strong eff
Li-rich layered oxides are considered as one of the most promising cathode materials for secondary lithium batteries due to their high specific capacities, but the issue of continuous voltage decay during cycling hinders their market entry. Increasing the Ni content in Li-rich materials is assumed to be an effective way to address this issue and attracts recent research interests. However, a high
Ethylene carbonate (EC) is the archetype solvent in Li-ion batteries. Still, questions remain regarding the numerous possible reaction pathways of EC. Although the reaction pathway involving direct EC reduction and SEI formation is most commonly discussed, EC ring-opening is often observed, but seldomly addressed, especially with respect to SEI formation. By applying Online Electrochemical Mass Sp
Although the two active redox centers in Li-rich cathodes, including the anionic and cationic contributions, can enable Li-ion batteries to achieve outstanding specific energy, their behaviors at different current densities have not been clarified. Here, we provide a comparative study of transition metals (TMs) and oxygen redox activities by directly accessing their oxidation states in Li-rich mat
Aqueous rechargeable batteries are appealing alternatives for large-scale energy storage. Reversible cycling of high-energy aqueous batteries has been showcased using highly concentrated aqueous electrolytes, which lead to a significantly suppressed water activity and formation of a stable solid-electrolyte interphase (SEI). However, the high salt concentration inevitably raises the cost and compr
Recent progress in “water-in-salt” electrolytes (WiSEs) and “hybrid aqueous/non-aqueous electrolytes (HANEs)” made broader choices of active material in aqueous Li-ion batteries (ALIBs), because of their compared to standard aqueous electrolytes expanded electrochemical stability windows (ESWs). Exploring high energy density ALIBs is a consequently meaningful research topic. However, the formation
Rechargeable aqueous zinc batteries (AZBs) have been recognized as attractive energy storage devices because of their intrinsic superiorities, e. g., high safety, low material cost and environmental benignity. However, challenges such as dendrite formation on the surface of zinc (Zn) anode, poor reversibility of Zn plating/stripping and short circuit of the cell, having detrimental impact on cycle
The development of high safety lithium-ion batteries (LIBs) is greatly impeded by the flammability and leakage concerns of typical organic solvent-based electrolytes. As one of the alternative classes of electrolytes, hydrogel electrolytes exhibit high safety, high flexibility, low cost, and are benign to the environment. However, the narrow electrochemical stability window (ESW) of typical hydrog
The formation of solid-electrolyte interphase (SEI) in “water-in-salt” electrolyte (WiSE) expands the electrochemical stability window of aqueous electrolytes beyond 3.0 V. However, the parasitic hydrogen evolution reaction that drives anode corrosion, cracking, and the subsequent reformation of SEI still occurs, compromising long-term cycling performance of the batteries. To improve cycling stabi
The introduction of “water-in-salt” electrolyte (WiSE) concept opens a new horizon to aqueous electrochemistry that is benefited from the formation of a solid-electrolyte interphase (SEI). However, such SEI still faces multiple challenges, including dissolution, mechanical damaging, and incessant reforming, which result in poor cycling stability. Here, we report a polymeric additive, polyacrylamid
Sodium ion batteries have been considered as promising alternatives to lithium ion batteries for large-scale renewable energy and smart grids applications due to their low cost and rich resources. However, critical drawbacks such as low energy density and poor stability are hindering their development and application. In this work, a stable symmetric sodium ion cell using sodium vanadium pyrophosp
The incorporation of inorganic lithium superionic conductors in polymer/ceramic composite electrolytes has been frequently proposed since this approach is expected to take advantage of the high ionic conductivities of the lithium superionic conductors and the elasticity of the polymer constituents of the composites. Nevertheless, the properties and mechanisms of polymer/ceramic composite electroly
Anatase TiO2 is recognized as a promising negative electrode material when employing “water-in-salt” electrolytes in high voltage aqueous lithium-ion batteries. However, the catalytic property of water splitting aggravates the hydrogen evolution reaction, which hinders the formation of a stable solid electrolyte interphase (SEI) on the electrode surface and therefore results in poor cycling perfor
Voltage decay during cycling is still a major issue for Li-rich cathodes in lithium ion batteries. Recently, the increase of Ni content has been recognized as an effective way to mitigate this problem, although it leads to lower-capacity materials. To find a balance between voltage decay and high capacity, particles of Li-rich materials with concentration gradients of transition metals have been p
In this work, a three-dimensional TiO2-graphene composite with large specific surface area is designed by freeze drying. In this architecture, primary TiO2 nanoparticles (less than 10 nm in size) are wrapped with graphene homogeneously, forming spherical secondary particles (≈100 nm), and the spherical TiO2 particles further agglomerate into platelet-like particles with several micrometers in size
Tin modified sodium manganese hexacyanoferrate, as a Prussian blue analogue, is studied as a cathode material for sodium ion batteries. By co-precipitation of Sn4+ during the synthesis process, the modified sodium manganese hexacyanoferrate materials crystallize with face-centered cubic structure with space group Fm3¯m, while the unmodified one possesses a rhombohedral structure with space group R
A series of Na0.67Ni0.33Mn0.67-xSnxO2 (x = 0, 0.01, 0.03, 0.05) materials with mixed P2/P3 phases are synthesized with a conventional solid-state reaction method and investigated as cathode materials for sodium ion batteries. The effects of Sn substitution on the structure and electrochemical performance of the Na0.67Ni0.33Mn0.67O2 are systematically investigated. The substituted samples show smal
