Flattening of Lithium Plating in Carbonate Electrolytes Enabled by All‐In‐One Separator
Yong Min Kim, Hyun‐seung Kim, Bo Keun Park, Jin Hyeok Yang, Han Jun Leem, Ji‐Sang Yu, Siwon Kim, So Yeun Kim, Jong‐Won Lee, Min‐Sik Park, Ki Jae Kim
Abstract
Abstract The uncontrollable dendritic growth of metallic lithium during repeated cycling in carbonate electrolytes is a crucial obstacle hindering the practical use of Li‐metal batteries (LMBs). Among numerous approaches proposed to mitigate the intrinsic constraints of Li metal, the design of a functional separator is an attractive approach to effectively suppress the growth of Li dendrites because direct contact with both the Li metal surface and the electrolyte is maintained. Here, a newly designed all‐in‐one separator containing bifunctional CaCO 3 nanoparticles (CPP separator) is proposed to achieve the flattening of Li deposits on the Li electrode. Strong interactions between the highly polar CaCO 3 nanoparticles and the polar solvent reduces the ionic radius of the Li + ‐solvent complex, thus increasing the Li + transference number and leading to a reduced concentration overpotential in the electrolyte‐filled separator. Furthermore, the integration of CaCO 3 nanoparticles into the separator induces the spontaneous formation of mechanically‐strong and lithiophilic CaLi 2 at the Li/separator interface, which effectively decreases the nucleation overpotential toward Li plating. As a result, the Li deposits exhibit dendrite‐free planar morphologies, thus enabling excellent cycling performance in LMBs configured with a high‐Ni cathode in a carbonate electrolyte under practical operating conditions.