Dual-assisted silicon nanoparticles with inorganic carbon-MXene and organic poly(3,4-ethylenedioxythiophene) shells for high-performance lithium-ion batteries

Abstract

Silicon-based (Si-based) materials have been highlighted for their high specific capacity and abundant reserves. However, the limited electrical conductivity and the large volume expansion are critical barriers to their extensive application. The most targeted remedy is the incorporation of selected conductive materials and the tailored design of electrode structures. Herein, carbon-MXene (C-MXene) and poly(3,4-ethylenedioxythiophene) (PEDOT) were employed to decorate Si cores to obtain Si-x@C-MXene@PEDOT particles. Among them, the content of Si was regulated for an optimal electrochemical performance. More significantly, given that the common single-layer core-shell structure was inherently inadequate in resisting the volume change, the core-bishell structure offered a robust buffer layer that consisted of a hard inorganic C-MXene and an organic PEDOT coating with an elastic conductive network, which collaboratively addressed the volume expansion issue. The resulting Si-2@C-MXene@PEDOT also possessed an excellent conductivity-promoting layer consisting of C-MXene and PEDOT, which facilitated the rapid transport of electrons, thus significantly boosting the electrochemical performance of the final electrodes. Also, the core-bishell structure assisted in the formation of a thinner solid electrolyte interface (SEI) film, which avoided the massive consumption of Li+ and enhanced the lithium storage capability. This work was expected to open up possibilities for larger-scale applications of Si-based materials.