Enhanced Cycleability of Micron-Size Silicon Anode by In Situ Polymerized Polymer Electrolyte

Silicon is widely recognized as an ideal anode material due to its high specific capacity, low lithiation potential, high abundance, and environmental friendliness. Nevertheless, the immense volume expansion during the lithiation leads to pulverization of silicon particles, which causes electrode failure with a rapid capacity decay. Herein, the polymerized 1, 3-dioxolane (PDOL) electrolyte is used to stabilize the micro-silicon Si anode via in situ polymerization route. The conformality of the quasi-solid electrolyte suppresses the pulverization of the Si microparticles (SiMPs) effectively and thus alleviates the capacity decay. The SiMPs/PDOL anode shows an excellent initial CE of 97.5% and maintains a reversible capacity of 1837.1 mAh g-1 at 500 mA g-1 after 100 cycles. The Si/PDOL/LiFePO4 full cells also exhibit a stable cycling performance with a capacity retention of 76.3% after 300 cycles. This work provides a new and easy path for the practical application of silicon anode at low cost. An optimized in situ polymerized electrolyte is developed to stabilize the micrometer-size silicon anode. With the optimized in situ polymerized electrolyte, the Li-Si half cells exhibit a high initial CE of 97.5% and a stable cycle performance over 100 cycles (with a residual capacity of 1837 mAh g-1); the Si-LiFePO4 full cell can operate stably over 300 cycles at 0.5C. image