Adsorption-catalysis design with cerium oxide nanorods supported nickel-cobalt-oxide with multifunctional reaction interfaces for anchoring polysulfides and accelerating redox reactions in lithium sulfur battery

Abstract

The charge and discharge working mechanisms in lithium sulfur batteries contain multi-step complex reactions involving two-electron transfer and multiple phase transformations. The dissolution and diffusion of lithium polysulfides cause a huge loss of active material and fast capacity decay, preventing the practical use of lithium sulfur batteries. Herein, CeO2 nanorods supported bimetallic nickel cobalt oxide (NiCo2Ox) was investigated as a cathode host material for lithium sulfur batteries, which can provide adsorption-catalysis dual synergy to restrain the shuttle of polysulfides and stimulate rapid redox reaction for the conversion of polysulfides. The polar CeO2 nanorods with abundant surface defects exhibit chemisorption towards lithium polysulfides and the excellent electrocatalytic activity of NiCo2Ox nanoclusters can rev up the chain transformation of lithium polysulfides. The electrochemical results show that the battery with NiCo2Ox/CeO2 nanorods can demonstrate high discharge capacity, stable cycling, low voltage polarization and high sulfur utilization. The battery with NiCo2Ox/CeO2 nanorods unveils a high specific capacity of 1236 mAh g−1 with a very low capacity fading of 0.09% per cycle after 100 cycles at a 0.2C current rate. Moreover, the excellent performance with high sulfur loading (>5 mg cm−2) verifies a huge promise for future commercial applications.