Enveloping a Si/N-doped carbon composite in a CNT-reinforced fibrous network as flexible anodes for high performance lithium-ion batteries

Abstract

Due to its highest theoretical capacity and low discharge potential, silicon (Si) has attracted increasing attention as one of the most promising anodes for lithium-ion batteries. However, the practical application of Si-based materials is still hindered by rapid capacity fading caused by the huge volume changes of Si during cycling. Herein, a flexible carbon nanotube (CNT)-constructed carbonaceous fibers network anchored with N-doped carbon-coated Si nanoparticles (C/Si/CNTs) has been fabricated. CNTs were sequentially bound together to form a fibrous structure and further crosslinked into a network by electrospinning method. The rational designed conductive network improves the electron transport, buffers the volume changes of inner Si nanoparticles and exhibits excellent mechanical flexibility. Utilized as flexible anodes for lithium-ion batteries, the C/Si/CNTs electrode delivers a high reversible capacity of 696.8 mA h g⁻¹ after 50 cycles at 100 mA g⁻¹, and achieves 473.1 mA h g⁻¹ at 500 mA g⁻¹ (based on the total mass of the electrode). This approach provides a promising strategy to develop high performance silicon-based anode materials for next-generation lithium-ion batteries.