Achieving stable lithium metal anodes via the synergy of electrostatic shielding and the high Li+ flux inorganic interphase†

Abstract

Uncontrolled dendrite growth and slow Li⁺ transport kinetics at the anode/electrolyte interface severely hamper the practical applications of lithium metal batteries (LMBs). Herein, a high–charge density cationic polymer, poly(octaallyltetraazacyclo–decane nitrate) (POTA–NO₃), was developed as an anodic protective layer to moderate Li⁺ deposition and enhance Li⁺ transport efficiency. According to Li⁺ deposition characteristics and simulation, POTA–NO₃ with multiple positive charge sites provided excellent electrostatic shielding and enhanced Li⁺ desolvation process to the anodes. Meanwhile, anions generated a robust and high Li⁺ flux inorganic SEI to inhibit the polymer cationic layer and electrolyte decomposition. With the POTA–NO₃ protective layer, Li||Li symmetric batteries achieved a stable cycling of 6300 h at a high current density of 5 mA cm⁻² with a capacity of 5 mA h cm⁻². Furthermore, the POTA–NO₃-protected Li||LiCoO₂ batteries exhibited a capacity retention of over 80% after 1400 long-term cycles at 1C. This work opens up the possibility for the development of stable lithium anodes.