Interfacial stabilization of lithium metal anodes in propylene carbonate electrolytes with tris(trimethylsilyl) phosphite

Although lithium (Li) metal is considered a next-generation material owing to its high theoretical capacity, several challenges restrict its use, such as rapid dendrite formation and continuous decomposition of the electrolyte at the interfaces. In this regard, we propose tris(trimethylsilyl) phosphite (TMSP) as an effective additive for stabilizing Li metal anodes in the presence of propylene carbonate (PC) solvent. Incorporating the TMSP additive into PC-based electrolytes provides a highly stable and robust interface at the Li anode because the TMSP additive facilitates the formation of LiSiO_x and Li_xPO_yF_z-based solid electrolyte interfaces (SEI) at the Li anode. These stable TMSP-derived SEI layers inhibit the uneven dendritic Li growth at the anode interface, effectively preventing further decomposition of the PC-based electrolyte. In Li/NCM622 cells, the TMSP-P-SE exhibited stable cycling retention after 100 cycles (72.3%), whereas the P-SE revealed a drastic decrease in cycling retention after only 10 cycles. These results indicate that the SEI formed on the Li anode in the presence of TMSP effectively inhibits parasitic reactions, thereby enhancing cycling retention significantly.