High-Capacity and Long-Lived Silicon Anodes Enabled by Three-Dimensional Porous Conductive Network Design and Surface Reconstruction

Silicon (Si) has an ultrahigh theoretical capacity of 4200 mAh g–1, which is one of the most promising anode materials for high-energy-density lithium-ion batteries (LIBs). However, the disadvantages of Si anodes, such as low electrical conductivity and large volume expansion, seriously impede their commercial application. Herein, we present an integrated strategy for the synthesis of three-dimensional (3D) porous Si@MXene@3-aminopropyltriethoxysilane (SMA) composite electrode. Based on the strategy of electrostatic self-assembly and surface reconstruction, the SMA composite with a 3D conductive network structure is successfully prepared by using 3-aminopropyltriethoxysilane (APTES) as a coupling agent for simultaneous surface reconstruction of nano-Si and MXene nanosheets, which enables fast electron/ion conduction pathways and high structure stability. Consequently, the SMA composite electrode exhibits an extremely high initial Coulombic efficiency (ICE, 90.9%), excellent cycling stability (with a high capacity of 2258 mAh g–1 at a current density of 0.5 A g–1 after 105 cycles), and good rate performance. In summary, the rational strategy concerning the 3D conductive network design and surface reconstruction boosts the electrochemical performances of the Si anode for LIBs.