Atomic interlamellar ion path in polymeric separator enables long-life and dendrite-free anode in lithium ion batteries

Abstract

Separator-lithium anode interface featured with uniform lithium-ion plating/stripping is of paramount importance for the safe operation of batteries. Lithium anode paired with traditional polyolefin separator is considerably challenged with uncontrolled formation of Li dendrites, giving rise to undesirable rate capacity and cycle life. In this work, through an electrophoretic deposition technique, hexafluoropropylene separator embedded with atomic interlamellar lithium-channel phyllosilicate clay is realized. With large absorption with electrolyte, the separator with interlamellar spacing of 1.31 nm provides abundant active sites for Li+ and enables fast transfer of lithium ions, giving rise to an ionic conductivity of 5.66 × 10−4 S cm−1 at ambient temperature. The parallel interlayers unify the direction of Li+ flows, which leads to the uniform deposition of Li+ on the anode and effectively eliminates lithium dendrite issues in Li+ plating/stripping processes. The cell assembled with the robust polymer/clay separator is more advantageous than state-of-the-art in the literature, delivering a reversible capacity of 152 mAh g−1 with a 98.5% capacity retention after 300 cycles at 0.5C.