Constructing a composite lithium anode for high-performance solid-state lithium-metal batteries via in-situ alloying reaction

Solid-state lithium-metal batteries (SSLMBs) with ceramic Li6.4La3Zr1.4Ta0.6O12 (LLZTO) electrolytes are widely deemed to be a viable candidate for high-energy storage devices with attractive safety. However, inadequate contact, dramatical volume variation and dendrite growth severally impede their practical applications. Herein, a composite Li metal anode consisting of LiF and CaLi2 alloy is constructed by in-situ alloying reaction of Li and minute amount of CaF2. The as-formed CaLi2 alloy and LiF in the composite Li metal anode not only improve the wettability of molten lithium to LLZTO by decreasing the surface tension, but also achieve the intimate contact and avoid anode volume collapse. The interfacial resistance is successfully decreased from 405.9 to 12.9 Omega cm(2) by adopting the composite Li as electrodes. The symmetric cells can cycle at 0.1 mA cm(-2) for 1000 h, and cycle at 0.2 mA cm(-2) for 580 h. In addition, SSLMB by using LiFePO4 (LFP) as the cathode exhibits a capacity retention of 70.9% after 125 cycles at 0.3 C as well as good rate performance. This work puts forward a rational and economic strategy to pave the path for the advance of SSLMBs.