Specific Adsorption-Oxidation Strategy in Cathode Inner Helmholtz Plane Enabling 4.6 V Practical Lithium-Ion Full Cells

Increasingthe cutoff voltage effectively maximizes the availablecapacity of the state-of-art layered-oxide cathodes (LiTMO2). However, the spontaneous dehydrogenation-oxidation of carbonatesin the cathode inner Helmholtz plane (C-IHP) under high voltage/temperatureleads to side effects, including weak cathode electrolyte interphase(CEI) and cathode structural collapse. Here, we report a specificadsorption-oxidation (Ad-O) mechanism that dominates the later CEIformation through molecular regulation in C-IHP. The two tailoredadditives with specific electron-rich groups will enter the C-IHPand mask the active sites of cathodes, thereby reducing the weak CEIgeneration from conventional carbonates. As-formed hierarchical CEIwith inner LiF and outer B-F/-CN rich organic structure willfurther protect the aggressive cathode from harmful electrolyte corrosionunder harsh conditions of high voltages (4.6 V) and elevated temperatures(60 & DEG;C). This synergistic strategy guided by the specific Ad-Omechanism enables 3.5 Ah LiNi0.8Co0.1Mn0.1O2/Graphite pouch cells, which remarkably achieve270 Wh/kg with 450 cycles.

Automated summary

A specific adsorption-oxidation (Ad-O) mechanism is used to regulate the formation of cathode electrolyte interphase (CEI) in the cathode inner Helmholtz plane (C-IHP), reducing the damage caused by conventional carbonates. The as-formed hierarchical CEI provides protection for the cathode under high voltage and elevated temperature conditions.