Polymeric artificial solid/electrolyte interphases for Li-ion batteries

During the operation of Li-ion batteries (LIBs), solvent and electrolyte decomposition takes place at the electrode surface to form a so-called solid-electrode interphase (SEI) passivating-layer. The physical structure and chemical composition of the SEI exert profound effects on various aspects of the electrode performance of the batteries. A new concept of forming polymeric artificial SEIs (A-SEIs) based on rational design of multifunctional polymer-blend coating to achieve favorable electrode/A-SEI/electrolyte interfacial properties is described. Three examples using binary and ternary polymer blends to form mechanically robust and highly Li-ion permeable surface coatings with selected functionalities in the cases of graphite and silicon–graphite composite electrodes have demonstrated greatly enhanced capacity, rate and cycle performance. Given the rich chemistry available from polymer blends, this surface preconditioning approach holds great promise for improving the performance of various negative electrodes to meet the requirements for advanced LIBs.