Lithium Batteries and the Solid Electrolyte Interphase (SEI)—Progress and Outlook

摘要

Interfacial dynamics within chemical systems such as electron and iontransport processes have relevance in the rational optimization of electrochemicalenergy storage materials and devices. Evolving the understandingof fundamental electrochemistry at interfaces would also help in the understandingof relevant phenomena in biological, microbial, pharmaceutical,electronic, and photonic systems. In lithium-ion batteries, the electrochemicalinstability of the electrolyte and its ensuing reactive decomposition proceedsat the anode surface within the Helmholtz double layer resulting in a buildupof the reductive products, forming the solid electrolyte interphase (SEI). Thisreview summarizes relevant aspects of the SEI including formation, composition,dynamic structure, and reaction mechanisms, focusing primarily onthe graphite anode with insights into the lithium metal anode. Furthermore,the influence of the electrolyte and electrode materials on SEI structureand properties is discussed. An update is also presented on state-of-theartapproaches to quantitatively characterize the structure and changingproperties of the SEI. Lastly, a framework evaluating the standing problemsand future research directions including feasible computational, machinelearning, and experimental approaches are outlined.