Improvement of Cycle Stability for Graphite-Based Lithium-Ion Batteries via Usage of Phenyl Methanesulfonate as an Electrolyte Additive

In this work, phenyl methanesulfonate (PMS) is evaluated as an additive to enhance the cyclic stability of lithium-ion batteries (LIBs) based on a graphite electrode. According to the theoretical results obtained from density functional theory (DFT) calculations, PMS possesses a lower reduction potential compared to the cyclic carbonate electrolyte solvent. Hence, this compound is foreseen to be reduced before ethylene carbonate (EC) and form a solid electrolyte interphase (SEI) layer on the graphite electrode. The cyclic stability of Li/graphite battery is promoted considerably by adding a low dose of PMS to the electrolyte. The capacity retention of the Li/graphite half-cell is incredibly improved to about 100% after 35 cycles at room temperature. The results acquired from the electrochemical and surface characterization tests corroborate that an electrolyte with PMS is capable of forming a thinner SEI layer compared to the electrolyte devoid of an additive, which can dramatically lessen the interfacial resistance. Moreover, the results show that the graphite sheets are disguised under a myriad of PMS reductive deposits, which can neutralize the catalytic activity of prismatic surfaces.