Rational design of a self-supporting skeleton decorated with dual lithiophilic Sn-containing and N-doped carbon tubes for dendrite-free lithium metal anodes

Abstract

The commercial application of lithium (Li) metal batteries is hindered by Li dendrite related severe safety issues. Herein, a functional self-supporting skeleton decorated with dual lithiophilic Sn-containing and N-doped carbon tubes (DLCTs) is constructed by one-step in situ carbothermal reduction for regulating the Li nucleation and inhibiting the generation of Li dendrites. Through the ingenious design, the formation of the reduced Sn nanoparticles and the growth of DLCTs can be simultaneously achieved. Benefiting from the superior lithiophilicity of Sn nanoparticles and N-containing groups, homogeneous distribution of Li ions, guided Li deposition and reduced side reactions are achieved with enhanced electrochemical performances. The DLCTs-based Li metal battery delivers an ultrahigh coulombic efficiency of 99.5% for 300 cycles at 3 mA cm⁻² and a superior performance over 1200 h with a low voltage hysteresis of 40.5 mV at 2 mA cm⁻² with a capacity of 2 mA h cm⁻². Besides, when coupled with an LiFePO₄ cathode, the DLCTs@Li|LFP full cell exhibits high reversible capacities of 121.7 and 93.9 mA h g⁻¹ with capacity retention ratios of 88.6% and 85.2% after 300 cycles when cycled at 1C and 5C, respectively. The construction of this lithiophilic framework shows great significance in promoting the practical applications of Li metal batteries.