Vertical growth of a 3D Ni–Co-LDH/N-doped graphene aerogel: a cost-effective and high-performance sulfur host for Li–S batteries

Abstract

Sulfur hosts and conversion catalysts based on NiCo-LDHs exhibit potential for improving the performance of Li–S batteries. Nevertheless, their low electron conductivity and aggregation propensity restrict their applicability. This investigation employs a temporary scaffold of ZIF-67 to produce a nanotube assembly of Ni–Co-LDH encapsulated within an N-doped graphene sponge. The electrochemically developed interface has an extended active surface area, and the clumping of LDH nanosheets is effectively inhibited by the design of the nanotube arrangement. Furthermore, the incorporation of nitrogen within the structure of graphene results in a boost of electrical conductivity and provides an increased quantity of active sites. Interfacial electron transport is facilitated by the interfacial rearrangement of charges resulting from p–n heterojunctions and fosters redox activity. In this study, the researchers have presented the double role played by the nickel–cobalt layered double hydroxide (NiCo-LDH) nanotubes in improving the polysulphide (LiPS) conversion and decreasing the movement of the sulphur (S) ions by forming surface-bound intermediates. The battery that was fabricated using the above composite cathode mixture showed a higher energy storage ability, i.e., 1190.0 mA h g⁻¹ at J = 0.2. Furthermore, the battery showed a significantly higher capacity to rapidly supply energy and displayed a rate capacity of 670.1 mA h g⁻¹ at J = 5C. Also, the above battery displayed a longer cycle life, with 1000 charge–discharge cycles and the deterioration rate of 0.029% for each cycle.