Uniform lithium deposition and dissolution via metallic phosphides medium for stable cycling lithium metal batteries

Abstract

Due to high theoretical specific capacity and low redox potential, metallic lithium attracts much attention as the “Holy Grail” anodes for next generation of high energy density lithium metal batteries (LMBs). However, coulombic efficiency decayes severely and safety hazards induced by Li dendrite growth during cycling process suppresses its practical application. In this contribution, nickel phosphides are first revealed to be beneficial for uniform lithium nucleation and growth. The constructed vertical nickel phosphides nanosheets show strong affinity to Li and good electron conductivity, and can react with Li ions to form a Li3P-riched interface, providing high Li ion conductivity to homogenize Li+ flux. The Li-interacted nickel phosphides also can function as a lithium reservoir to compensate the irreversible Li loss, thus enabling high coulombic efficiency of 98.5% at 1 mA cm−2 for 280 cycles. It also shows superior cycling stability over 3000 h in a symmetric cell. As a result, not only can high coulombic efficiency and extraordinary stability be reached, but also excellent cycling stability and better rate performance be realized when paired in full cell with LiFePO4 cathode. Our results highlight the new strategy for the utilization of metal phosphide as lithiophilic layer for suppressing dendrites in LMBs.