Hollow Ni-Co-S Nanocubes as Superior Sulfur Host for High-Performance Lithium-Sulfur Batteries

Abstract

In this work, hollow Ni-Co-S nanocubes were designed and successfully prepared as a superior sulfur host for lithium-sulfur batteries (LSBs) by means of facile synthesis methods. The prepared hollow Ni-Co-S nanocubes possess multiple merits, including good electrical conductivity, sulfur encapsulated nanostructure and LiPS adsorbability. By employing Ni-Co-S nanocubes as the sulfur host, the electron transfer efficiency is incresed and the volume expansion during repeated cycling can be buffered. Besides, the shuttling effect is limited effectively due to the strong lithium polysulfides (LiPS) adsorbability. As a result, the sulfur utilization is significantly improved for better performance. Benefiting from these advantages, the LSBs exhibited a fairly high initial capacity of 1482 m Ah g-1, a retained capacity of 669 m Ah g-1 over 200 cycles and impressive discharge capacities of 710, 565, 370 and 186 m Ah g-1 even at 1C, 2C, 3C and 4C, respectively.