Highly lithiophilic and structurally stable Cu–Zn alloy skeleton for high-performance Li-rich ternary anodes

The novel ternary Li–Cu–Zn alloy is not a simple mixture of Li–Cu and Li–Zn alloys. Its delithiation skeleton is composed of highly lithiophilic and stable “Li-inactive” CuZn and “Li-active” CuZn5 phases, effectively suppressing dendrite formation and volume changes in lithium metal anode. [Display omitted] •Multiple alloying reactions in multicomponent Li-rich alloy were discovered for the first time and two new skeletons, i.e., CuZn and CuZn5 were formed in the Li–Cu–Zn ternary alloy.•The CuZn5 skeleton is “Li-active” and the CnZn skeleton is “Li-inactive”, both of which exhibit superior lithiophilicity and structural stability.•Li–Cu–Zn ternary alloy can mitigate the huge volume change during cycling.•The synergistic effect of CuZn and CuZn5 realizes a dendrite-free Li deposition behavior. Lithium (Li)-rich ternary alloy, comprising a multi-alloy phase as the built-in three-dimensional (3D) framework and a Li metal phase as a reversible Li reservoir, is a promising high-energy–density anode for rechargeable Li metal batteries. The introduction of metal/metalloid components to the alloy can effectively regulate Li deposition and maintain the dimensional integrity of the Li anode. Herein, the lithium–copper–zinc (Li–Cu–Zn) ternary alloy, as a new type of alloy anode, is synthesized via a facile thermal melting method. The fully delithiated 3D scaffold comprised two Cu–Zn alloy phases named CuZn and CuZn5. These alloy phases exhibit higher lithiophilicity and structural stability than Li–Zn and Li–Cu alloys. Moreover, the CuZn phase is electrochemically inert, ensuring the geometric stability of the anode, while the CuZn5 phase can readily undergo alloying reaction with Li to form the LiZn phase, thereby facilitating uniform Li nucleation and deposition. The hybridized multiphase alloy structure and specific energy storage mechanism of the Cu–Zn based alloy scaffold in the ternary alloy anode facilitate dendrite-free Li deposition and prolonged cycle lifetime. The Li metal full battery based on lithium iron phosphate (LiFePO4) cathode exhibits high cycling stability with high-capacity retention of 95.4% after 1000 cycles at 1C.