Tailoring the growth route of lithium peroxide through the rational design of a sodium-doped nickel phosphate catalyst for lithium–oxygen batteries

Abstract

Tailoring the morphology and structure of Li₂O₂, the discharge product of lithium–oxygen batteries (LOBs), through the rational design of cathode catalysts is an efficient strategy to promote the electrochemical performance of LOBs. In this work, sodium-doped nickel phosphate nanorods (Na–NiPO NRs) grown on Ni foam (NF) were prepared by the hydrothermal method and subsequent calcination. For the Na–NiPO NRs, the electronic structure could be optimized and abundant void space among the nanorods would provide abundant transport channels. Adopted as the cathodes, the Na–NiPO NRs could facilitate the uniform growth of sea cucumber-like Li₂O₂ with sufficient Li₂O₂-electrolyte and Li₂O₂-catalyst interfaces, significantly promoting the charge process. Therefore, LOBs could deliver a high discharge capacity of 10365.0 mA h g⁻¹ at 100 mA g⁻¹. And a low potential gap of 1.16 V can be achieved at 200 mA g⁻¹ with a capacity of 500 mA h g⁻¹. The proposed strategy demonstrates the role of the morphology and electronic structure of the cathode catalysts in tuning the Li₂O₂ morphology and provides a novel approach for achieving high-performance LOBs.