Dual network porous Si/Al9 FeSi3/Fe2O3 composite for high performance Li-ion battery anode

Silicon (Si) is regarded as the most prominent anode material for lithium ion batteries (LIBs) because of its high theoretical specific capacity. However, Si-based anodes suffer from fast capacity degradation caused by drastic volume expansion/contraction during repeated charge/discharge process and accompanying internal mechanical strain. Herein, we report a new dealloying strategy to synthesize a dual network porous Si/Al9FeSi3/Fe2O3 composite, which can release the internal stress and accommodate the volume changes of the anode during cycling. The anode presents a high Li storage capability, revealing an excellent reversible capacity of 1100 mAh g(-1) at 200 mA g(-1) for 150 cycles and 378 mAh g(-1) at 4000 mA g(-1) for 500 cycles. Such outstanding Li storage properties can be attributed to the special dual network porous structure and compositing the materials with high and low theoretical capacities. The work provides a new route to design and prepare low-price and high-performance Si-based anodes, which opens new avenues for the technical progress in dealloying preparation and the development of advanced high performance anode materials. (C) 2020 Elsevier Ltd. All rights reserved.