Bimodal nanoporous NiO@Ni–Si network prepared by dealloying method for stable Li-ion storage

Abstract

Nickelous oxide (NiO) is a promising anode for Lithium ion (Li-ion) batteries. However it suffers from rapid degradation due to large volume change upon cycling. In this work, a novel strategy to accommodate the volume change of NiO-based anodes during charge/discharge cycling through employment of the advantages of bimodal porous Nickel–Silicon (Ni–Si) network and Nickelous oxide@Nickel (NiO@Ni) shell@core structure is proposed. The designed bimodal nanoporous NiO@Ni–Si network exhibits a stable Li-ion storage property with an extremely high reversible capacity of 1656.9 mAh g−1 at 200 mA g−1 after 300 repeated cycles and 1387.1 mAh g−1 at 500 mA g−1 after 1000 cycles. It also shows a good rate performance, delivering about 400 mAh g−1 even at a current density of 2000 mA g−1. Post-cycling microscopy and impedance studies reveals the minor changes in the electrode structure that, in turn, results in an extremely low capacity degradation rate of 0.03%/cycle. The employed strategy enriches the structural design idea of dealloying products, which may further promote the development of the dealloying field and can be applied in future to prepare various types of porous shell@core anodes for Li-ion battery applications.