Single-Atom Catalyzed Formation of Inorganic-Rich SEI/CEI for Durable Anode-Free Solid-State Lithium Metal Batteries

Abstract

Anode-free solid-state lithium metal batteries are promising for energy storage owing to their maximum energy density, safety, and cost-effectiveness. However, their practical application remains hindered by fragile electrode-electrolyte interfaces (EEI) and the resulting rapid active species depletion. Here, a single-atom catalysis strategy is proposed for the in-situ construction of inorganic-rich EEI by utilizing a single Ni atom anchored covalent organic framework (COF) as catalyst, which is incorporated into a polymer electrolyte. The B−O−Ni bridge on COF-5 accelerates the electron transfer to the TFSI− anion and improve the decomposition kinetics of lithium salt, thus building an inorganic-rich solid electrolyte interphase (SEI) to enable smooth Li deposition and remarkable interfacial stability. Additionally, the boron-based COF-5 generated B, F-rich cathode electrolyte interphase (CEI) inhibits the dissolution of transition metal ions and ensures the structural integrity of NCM cathodes upon cycling. Consequently, the NCM622||Li solid-state cell demonstrates an exceptional capacity retention of 92.0% over 1500 cycles at 1.0 C, while achieving a remarkable capacity of 172.4 mAh g-1 after 200 cycles at 0.2 C under a cutoff voltage of 4.7 V. Moreover, the anode-free NCM622||Cu solid-state pouch cell maintains a stable cycling over 200 cycles in the carbonate electrolytes. This study extends the single-atom catalysis into a platform to regulate lithium salt decomposition toward prolonged anode-free solid-state batteries.