A General Strategy of Anion-Rich High-Concentration Polymeric Interlayer for High-Voltage, All-Solid-State Batteries.

All-solid-state batteries are promising energy storage systems as a power source for future electric applications. However, the solid electrolytes have suffered from oxidative vulnerability at the catalytic cathode's surface, particularly at the high-voltage charging process. The poor charge transport and the contact issue at the electrolyte/electrode interface also hamper fully utilizing high-energy-density batteries. In this work, a general design of a high-concentration polymeric interlayer is developed. The interactions between a number of anions in the high-salt-concentration and the polymer chain's functional groups have shown outstanding physicochemical properties, including the rich solvation sites and conductive nanochannels, which Li+ ions can coordinate to or conduct through. The high-concentration polymeric interlayer is also highly resistant to oxidation (up to 5 V) that leads to significant improvement in cycle life with various cathodes, including LiNi1/3Co1/3Mn1/3O2, LiCoO2 and LiFePO4, demonstrating a high Coulombic efficiency over 99.9%.