Hybrid ionic/electronic interphase enabling uniform nucleation and fast diffusion kinetics for stable lithium metal anode

Abstract

Lithium (Li) dendrite issue, which is usually caused by inhomogeneous Li nucleation and fragile solid electrolyte interphase (SEI), impedes the further development of high-energy Li metal batteries. However, the integrated construction of a high-stable SEI layer that can regulate uniform nucleation and facilitate fast Li-ion diffusion kinetics for Li metal anode still falls short. Herein, we designed an artificial SEI with hybrid ionic/electronic interphase to regulate Li deposition by in-situ constructing metal Co clusters embedded in LiF matrix. The generated Co and LiF both enable fast Li-ion diffusion kinetics, meanwhile, the lithiophilic properties of Co clusters can serve as Li-ion nucleation sites, thereby contributing to uniform Li nucleation and non-dendritic growth. As a result, a dendrite-free Li deposition with a low overpotential (16.1 mV) is achieved, which enables an extended lifespan over 750 h under strict conditions. The full cells with high-mass-loading LiFePO4 (11.5 mg/cm2) as cathodes exhibit a remarkable rate capacity of 84.1 mAh/g at 5 C and an improved cycling performance with a capacity retention of 96.4% after undergoing 180 cycles.