Spatially controlled lithium deposition on LixCuyPz arrays enabling highly stable lithium metal batteries

Abstract

Lithium (Li) metal is a potential anode for high-energy-density batteries because of its low potential and ultrahigh capacity. Nevertheless, the Li dendrites formation, the ununiform Li deposition, and the growth of Li dendrites hamper its application, especially under high deposition capacity/high rate. Here, a spatially controlled Li deposition mode with array-oriented morphology is achieved based on the novel mixed ion/electron-conducting LixCuyPz arrays constructed on Cu foil, which can be facile fabricated via an in-situ transformation of metal phosphide. Theoretic calculations indicate the excellent lithiophilicity and low Li diffusion barrier of the arrays, especially for the Li2CuP phase, which are conducive to homogenizing the Li nucleation/deposition of Li. Moreover, such mixed conducting arrays promote fast Li+ diffusion via the continuous Li+ pathways as well as modulate the Li+ flux/electric field. Furthermore, the arrays with enlarged specific surface area and open spaces reduce the local current density and alleviate the volume fluctuation of Li. Consequently, a dendrite-free Li anode is obtained under a high rate (20 mA cm–2) or a high deposition capacity (10 mAh cm–2). In addition, even if the negative/positive ratio reduces to only 1.1, the full cells still perform outstanding stability for over 200 cycles. This work emphasizes the importance of the design of the framework in terms of the intrinsic properties and structure and reveals a pathway for developing Li metal batteries.