Electrode-electrolyte interface mediation via molecular anchoring for 4.7 V quasi-solid-state lithium metal batteries

Solid polymer electrolytes (SPEs), promising electrolyte candidates for lithium metal batteries (LMBs), still suffer from the great challenge of unstable solid-solid interface between the electrodes and SPEs. Herein, SPEs are modulated by trimethyl phosphate (TMP) molecular anchoring to reconstruct the Li+ solvation structure, satisfy the interfacial compatibility of electrolyte-electrode and further unlock ultra-high voltage quasi-solid-state lithium metal batteries. An ultra-long cycle life of over 9000 h is achieved in Li|Li symmetrical cell at 0.1 mA cm- 2. Furthermore, multiple highly-sensitive characterization techniques together with molecular dynamics simulations were applied to demonstrate that the in-situ induced stable cathode-electrolyte interface (CEI) rich in LiF, LixPFyOz and organic hybrids is responsible for the structural integrity of Ni-rich cathodes at 4.7 V ultra-high voltage. More importantly, the 91.55% capacity retention after 300 cycles of NCM811|Li full cell can well satisfy the practical application of high-voltage quasi-solid-state Li-metal energy storage systems.

Automated summary

Solid polymer electrolytes (SPEs) are modified by trimethyl phosphate (TMP) molecular anchoring to achieve stable solid-solid interface and unlock ultra-high voltage quasi-solid-state lithium metal batteries. The in-situ induced stable cathode-electrolyte interface (CEI) rich in LiF, LixPFyOz and organic hybrids contributes to the structural integrity of Ni-rich cathodes at 4.7 V ultra-high voltage. The NCM811|Li full cell retains 91.55% capacity after 300 cycles, meeting the requirements of high-voltage quasi-solid-state Li-metal energy storage systems.