Nickel aerogel @ ultra-thin NiCo-LDH nanosheets integrated freestanding film as a collaborative adsorption and accelerated conversion cathode to improve the rate performance of lithium sulfur batteries

Abstract

It is a great challenge to develop freestanding ultralight cathodes for lithium–sulfur battery exhibiting good electrochemical performances. Herein, ultrathin porous nickel–cobalt layered double hydroxide (NiCo-LDH) nanosheets were grown on the surface of ultra-light nickel microwire aerogels (NMWAs), and there is capillary action in the gaps formed by the ordered arrangement due to the presence of magnetic filed in the preparation process, which has the advantages of synergistic adsorption and accelerated conversion kinetics of lithium polysulfide. Because of the abundant hydrophilic hydroxyl groups on the surface of NiCo-LDH and the capillary action of NMWAs, the integrated freestanding film cathode sulfur host (NMWAs@NiCo-LDH/S) provides excellent rate performance as well as cycling stability. The film cathode has an ultra-high initial specific capacity of 1238.4 mAh/g at 0.1C and an excellent reversible capacity of 805.8 mAh/g at 5.0C. Even after 700cycles at a high current density of 5.0C, it still provides a reversible capacity of 647.1 mAh/g with a capacity decay rate of only 0.018 % per cycle. This work provides a simple and new way for the design of high rate lithium–sulfur battery film cathodes with good cycle stability.