Polar NiFe layered double hydroxide nanosheets for enhancing the performance of lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries are an attractive electrochemical energy storage system with high theoretical energy density. However, the application of Li–S batteries has been hindered by the rapid capacity fading due to the “shuttle effect”. Here, we demonstrate that polar NiFe layered double hydroxide (LDH) nanosheets, acting as protective hosts of polysulfides for the cathode, have a strong chemical interaction with sulfur species. The NiFe LDH hosts can effectively restrict the dissolution of polysulfides and enhance the reaction kinetics of lithium polysulfide redox reactions through the electrocatalytic effect. As a result, the NiFe LDHs/S electrode exhibits an excellent electrochemical performance with a high initial discharge capacity of 1633.5 mA h g⁻¹ at 0.2C and a stable cycle performance with a capacity decay of 0.024% per cycle at 2C.