Electrochemical Behavior of Li-Cu Composite Powder Electrodes in Lithium Metal Secondary Batteries

A new type of Li-Cu composite powder electrode (Li-Cu CE) was fabricated via mechanical blending of Li and Cu powders. The new Li-Cu electrode is capable of replacing Li metal anodes in Li metal secondary battery (LMSB) systems without exhibiting typical intrinsic problems such as dendrite growth, volume change, and electrolyte depletion. Thus, Li-Cu CE cells can offer longer lives and very high capacities. The Li particles in Li-Cu CEs are surrounded by Cu particles and thus cannot form networks that extend throughout the electrode. Isolation of the Li powder enables the control of Li⁺ ion migration during deposition and dissolution. The Li-Cu CE can thus prevent problematic volume changes and dendrite growth on the anode during battery operation. Symmetric Li-Cu CE cells are stable for up to 200 cycles at a rate of 3 C, and the anode capacity is estimated to be 1158 mAh g^-1 (Li⁺ ion usage of 30%). These results are thought to represent a largest anode capacity for Li-metal in LMSBs.