Toward Long-Life Lithium Metal Anode by a Li3N-Rich Architecture with Grafted Li Reservoirs

Abstract

Lithium (Li) metal anodes (LMA) are regarded as one of the most promising anode candidates due to their high theoretical capacity; however, Li dendrites and the volume expansion issues make their practical application very challenging. Herein, a lightweight and high nitrogen (N)-doped carbon fiber with grafted sphere-like carbon nanotubes (HN-SCNTgCFs) has been successfully fabricated as a Li platting matrix by a two-step strategy of surface engineering including solid resource assisted chemical vapor deposition (solid-CVD) and subsequent electrochemical conversion. Benefitting from this HN-SCNTgCF matrix with a fast Li⁺ conductor (Li₃N), the HN-SCNTgCFs || Li system behaves completely stable, i.e., 900 cycles with a CE of ∼100%; the quasi-Li-anode-free HN-SCNTgCFs || LiFePO₄ (LFP) cell delivers a long lifespan of 800 cycles; and the Li-HN-SCNTgCFs || LFP cell exhibits long cycling stability (1000 cycles) with a low capacity decay of 0.057 mA h g^–1 per cycle. These excellent results suggest that surface engineering is a feasible strategy for constructing an effective Li matrix to stabilize LMA.