Confining Silicon Nanoparticles within Freestanding Multichannel Carbon Fibers for High-Performance Li-Ion Batteries

With the properties of high specific capacity and low charge potential, silicon has been considered as one of the most promising candidates to replace the commercial graphite anode. However, the application of the silicon-based anode has been restricted by poor electronic conductivity and tremendous volume variation during its lithiation/delithiation, which leads to an unstable solid electrolyte interphase (SEI) and more side-reactions as well. To solve those challenges, herein, we synthesize multichannel carbon fibers (MC-CNFs) via a facile electrospinning–carbonization method and use it as a freestanding host for silicon nanoparticles (Si NPs). The Si NPs are distributed in the MC-CNFs to buffer their volumetric stresses and to stabilize the SEI layers, while the interconnected structure of the carbon fibers can effectively increase the conductivity of the composite electrodes. On fabricating a coin-type cell, the MC-CNF confined Si NP (Si@MC-CNFs) anode with an initial capacity of 1400 mAh g–1 and an initial Coulombic efficiency (ICE) of 87% delivers good cycle stability and rate performance.