Uniform lithium nucleation/deposition regulated by N/S co-doped carbon nanospheres towards ultra-stable lithium metal anodes

Abstract

Uncontrollable Li dendrite growth increases the risks of cell short-circuit or even safety accidents, severely hindering the practical application of lithium metal anodes (LMAs). Herein, N/S-co-doped mesoporous carbon (NSMC) nanospheres with ordered mesoporous channels prepared by an in situ polymerization and facile pyrolysis approach are designed and can effectively regulate the Li nucleation/deposition behavior. As a host, NSMC has high affinity towards Li ions owing to the electronegative surface, which provides a low Li nucleation barrier and promotes the subsequent dendrite-free deposition. Moreover, a robust solid electrolyte interphase (SEI) layer is established, synergistically improving the cycling stability, even under high areal capacity. With these advantages, ultra-stable Li@NSMC|Li@NSMC symmetric cells were achieved with a lifetime of up to 2700 h and 400 h at a high areal capacity of 4 and 20 mA h cm⁻², respectively. Full cells with commercial LiFePO₄ cathodes deliver a high reversible capacity of 121 mA h g⁻¹ after 300 cycles at 2C with a retention ratio of 84%, showing great potential in practical applications.