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As the pursuit of greater energy density for the portable battery has stimulated exhaustive research in high‐voltage lithium‐ion batteries (LIBs), developing electrolyte additives is considered a cost‐efficient way to improve the performance of the battery. Here, the three interactional issues of LiCoO2 (LCO) batteries in commercial electrolytes at high voltage are summarized, this review first identifies an unavoidable vicious cycle of the commercial electrolyte at high voltage. LCO/electrolyte interphase break, dissolution of transition metal (TM) ions, and formation of harmful HF accelerate the failing progress of the commercial electrolyte at high voltage, besides the malfunction of anode happens at the same time because of electrode crosstalk. Then, the modification of the commercial electrolyte is summarized according to the solutions of this vicious cycle. Last, a framework for future research on high‐voltage LCO batteries is outlined. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) have dominated the secondary batteries market in the past few decades. However, their widespread application is seriously hampered by the limited lithium resource and high cost. Recently, sodium‐ion batteries (SIBs) have generated significant attention because of their characteristics of abundant raw sources, low cost, and similar "rocking chair" mechanism with LIBs, which hold great application potential in large‐scale energy storage. Cathode materials with excellent electrochemical performance are in urgent demand for next‐generation SIBs. Herein, this review provides a comprehensive overview of the recent advances of the most promising SIBs cathode candidates, including layered oxides, polyanionic materials, and Prussian blue analogues. The currently existing issues that need to be addressed for these cathodes are pointed out, such as insufficient energy density, low electron conductivity, air sensitivity, and so on. This review also details the structural characteristics of these three cathode candidates. Moreover, the recent optimization strategies for improving the electrochemical performance are summarized, including element doping, morphology modification, structure architecture, and so on. Finally, the current research status and proposed future developmental directions of these three cathode materials are concluded. This review aims to provide practical guidance for the development of cathode materials for next‐generation SIBs. [ABSTRACT FROM AUTHOR]

To improve the safety and electrochemical properties of lithium ion batterie (LIB), a series of novel organic soluble poly(aryl ether ketone) (PAEK) copolymers were synthesized and used to fabricate LIB separators. The PAEK copolymers exhibited superior structural thermal stability and flame retardant, with glass transition temperature (Tg) above 150°C, oxygen index above 30 and no thermal decomposition before 500°C. Accordingly, the fabricated separators exhibited superior dimensional stability. The mechanical properties and electrolyte uptakes of the separators, as well as the electrochemical properties of the cells assembled with the separators were affected by the morphology and porosity of the separators. The separators with sponge‐like structure exhibited less electrolyte uptakes but better mechanical properties than that of the ones with finger‐like structure. The cell with finger‐like structure separator exhibited poorer electrochemical properties than sponge‐like structure separator, which might be caused by the collapse of some finger hole during the assemble process due to its poor mechanical properties. The charge–discharge performances of the cells after treated at 150°C demonstrates that the PAEK separators could be promising candidates for high‐safety LIB. [ABSTRACT FROM AUTHOR]