Binder-Free Intertwined Si and MnO₂ Composite Electrode for High-Performance Li-Ion Battery Anode

Silicon is considered as the most felicitous anode material candidate for lithium-ion batteries on account of abundant availability, suitable operating potential, and high specific capacity. Nevertheless, drastic volume expansion during the cycle impedes its practical utilization. Herein, Si and MnO₂ (Si-MO) constructed the binder-free intertwined electrode that is reported to effectively improve upon the cycling stability of Si-based materials. The Si-based electrode without a binder has good electrical conductivity, strong adhesion to the substrate, and ample space for mitigating volume expansion. The incorporation of MnO₂ establishes a multiphase interface, which mitigates the electrode volume expansion, and supports the electrode structure. Furthermore, MnO₂ (∼1230 mAh g^-1 theoretical capacity) synergistically enhances the overall capacity of the composite electrodes. Consequently, the Si-MO composite electrode exhibits a reversible specific capacity of 1300 mAh g^-1 at 420 mA g^-1 and remarkable cycling performance with a specific capacity of 830 mAh g^-1 after 500 cycles. In particular, a reversible specific capacity of 837 mAh g^-1 at 4200 mA g^-1 is achieved and remains stable during 200 cycles. This work provides a potentially feasible way to achieve the Si-based anode commercialization for LIBs.