Chemo-mechanical stable cathode interphase via interface in-situ catalytic-conversion integrated design for all solid-state batteries

All-solid-state lithium batteries (ASSLBs) based on LiNi1-x-yCoxMnyO2 cathode suffer from rock-ribbed electrolyte-cathode interface issues such as oxygen escape and side reactions with electrolyte at high operating voltage, result in severe structure deterioration and rapid capacity decay. Herein, a kind of synergistic “catalytic conversion” integrated mechanisms is strategically exploited to in-situ construct steerable cathode-electrolyte interface (CEI), intending to synchronously elevate electrochemical and structural stability upon cycling. By employing functional polypyrrole (PPy) as coating layer on high voltage-operated LiNi0.8Co0.1Mn0.1O2 (NCM811), we unveils that the N-H bond of polypyrrole ring can product N-H…O hydrogen bonding interaction to alleviate oxygen evolution. Detailed, through hydrogen bonding, higher reductive O- despoil proton-H to form OH-. The resulting astray OH- together with O2- further coordinated with Li+ around the aromatic skeleton interrupted by nucleophilic π-π interaction, thereby promoting the in-situ generation of Li2O-LiOH rich CEI. Finally, the parasitic interfacial side reactions and oxygen evolution are considerably suppressed, enabling the NCM@PPy full cell an excellent cyclic performance with a capacity retention of 81.2% after 300 cycles. Such in-situ generated Li2O-LiOH rich CEI enables NCM811 cathode to achieve considerable capacity of 122 mAh·g-1 at 0.5C with operating voltage of 4.3 V and lifetime of more than 100 cycles, demonstrating the practical application potential in energy storage field.