Operando Characterization of Dendrite-Free Silver Nanoparticle/Lithium Metal Powder Composite Anodes

Li metal powder (LMP) can be used to produce Li metal anodes that are wider and thinner than existing Li metal foils at a lower price; consequently, it is attracting attention as a promising anode material for secondary high-energy density Li metal batteries (LMBs). In the present study, operando microscopy is adopted to decipher the effects of a lithiophilic nanoadditive─Ag nanoparticles (AgNPs)─on the electrochemical behavior of LMP-based Li metal anodes. A composite Li metal anode is fabricated by implanting AgNPs into LMP, and the surface morphological changes and electrochemical behaviors are analyzed during electrochemical cycling. The obtained results provide deep insights into the role of AgNPs in stabilizing LMP-based Li metal anodes. Essentially, the AgNPs form a Li ion-conducting Li-Ag alloy during cycling and provide favorable large-area nucleation sites throughout the LMP-based Li metal anode, thereby suppressing vertical Li dendrite growth. Overall, a 40 μm thick Li metal anode of the AgNP/LMP composite (AgLMP) exhibits a stable cycling performance over 500 cycles, sustaining 73.6% of the initial discharge capacity at 0.3C (0.231 mA cm^-2, charging)/0.5C (0.385 mA cm^-2, discharging) in Li||NCM433 metal cells. This report highlights the viability of using AgNPs to boost the electrochemical performance of LMP electrodes.