Engineering a heteroatom-doped multidimensional carbon network for dendrite-free lithium metal anode

Abstract

Lithium metal anode (LMA) has attracted widespread attention on account of its highest theoretical capacity and low reduction potential. However, the practical application of LMA has been long hindered by safety concerns and huge volume change resulting from the inevitable lithium dendrites growth. Herein, a multidimensional framework consisting of commercial carbon cloth (CC) and N, S-codoped porous carbon (PNSC) net (CC@PNSC) is fabricated and applied for LMA. This CC@PNSC skeleton has a large specific surface area, and the local current density can be significantly decreased. In addition, the synergetic effect of nitrogen and sulfur codoping endows CC with enhanced lithiophilicity and even lithium plating behavior. More importantly, the in-situ formed Li3N and Li2S during the molten lithium infusion process facilitate Li+ transfer kinetics and effectively homogenize the Li+ flux diffusion. The as-prepared CC@PNSC-Li composite anode exhibits high specific capacity (3 mA h cm−2, 500 h) and impressive cycling stability with a flat voltage profile at a current density of 1 mA cm−2 (750 h). When paired with LiFePO4 (LFP), the LFP||CC@PNSC-Li cell delivers an extraordinary rate capacity (especially at 5C) and a long-term cycling lifespan at 1C (600 cycles and capacity retention of 89.06%).