Regulating Li uniform deposition by lithiophilic interlayer as Li-ion redistributor for highly stable lithium metal batteries

Abstract

Although Lithium (Li) metal anode possesses a high theoretical capacity and low redox potential, the poor cycling stability and safety concerns caused by Li dendrites seriously hinder the implementation of Li metal-based batteries. Herein, for the first time, we present a novel interlayer of lithiophilic W2N3 embedded N-doped graphene (WNG) as Li-ion redistributor to effectively adjust and redistribute the interfacial ionic flux. Due to its unique porous nanoarchitecture, WNG nanoflower can guarantee robust mechanical strength, excellent thermal stability and abundant Li deposition sites, meanwhile W2N3 nanoparticles with the abundant polar bonds can offer a strong interaction between Li atom and W2N3 to uniformly regulate the interfacial Li-ion flux thus effectively inhibiting the growth of Li dendrites. DFT calculations further confirms a strong interaction between Li atom and WNG, and the Li ion concentration using WNG/PP is 11.3 times lower than that using bare PP separator. As a result, the lithium metal batteries with WNG interlayer demonstrate dendrite-free and ultra-stable features: the Li//Li symmetric cells show ultralow overpotential (49.6 mV) at ultra-long-term cycling of 2000 h even at 5 mA cm−2 with 1 mAh cm−2; the Li//LiFePO4 full cells exhibit exceptionally ultra-low capacity decay rate of 0.06%/cycle after 300 cycles.