Zn-assisted low-temperature reconstruction of NiCo heterogeneous catalysts for lithium-oxygen batteries

Abstract

Developing catalysts with high catalytic activity and durability is an effective strategy for improving the electrochemical performance of lithium-oxygen batteries (LOBs). Metal atom doping and heterostructure construction have shown great potential in catalysis and are expected to be widely used in energy storage. In this study, a Zn-doped NiCo2O4/NiO heterostructured complex catalyst is designed and prepared as a cathode catalyst for LOBs. This metal-doped heterostructured complex catalyst, prepared at a lower annealing temperature, retains the most active sites. Additionally, the three-dimensional hollow structure of the catalyst not only facilitates mass transfer but also provides active sites through doping and heterostructure formation. The Zn-doped NiCo2O4/NiO catalyst exhibits excellent catalytic performance, resulting the generation of a silky Li2O2 discharge product film, and the higher adsorption energy for the intermediate product LiO2 also allows the discharge product to be tightly bound to the catalyst. The improved contact between the discharge products and the catalyst's active sites, along with the increased surface area, enhances charge transport and decomposition properties, leading to good reversibility of the LOB. Consequently, the LOB based on Zn-doped NiCo2O4/NiO heterostructure complex catalyst features high discharge capacity (12160 mAh/g at 200 mA g−1) and excellent durability (353 cycles, ∼1765 h). Furthermore, theoretical calculations show that the Zn-doped complex heterostructures have enhanced reaction kinetics of OER and ORR. This straightforward method of producing metal-doped heterostructured complex catalysts that induce uniform Li2O2 deposition valuable insights for enhancing the performance of LOBs.