Amorphous interface-controlled discharge product formation: A pathway to high-performance lithium-oxygen batteries

Abstract

Lithium-oxygen batteries (LOBs) can afford high-energy density storage, yet their commercialization is hindered by sluggish redox kinetics. To address this issue, we successfully constructed a self-supporting crystalline NiCo₂O₄ (NCO)/amorphous Ni_xP (NP) heterostructure (c/a) catalyst using a two-step electrodeposition strategy. This innovative design introduces a disordered amorphous structure, providing abundant active sites and accelerating ion diffusion. Density functional theory (DFT) calculations demonstrate that the c/a heterostructure remarkably reduces the work function and adjusts the Fermi level, thereby weakening the adsorption energy of LiO₂. This modulation allows LiO₂ to diffuse into the electrolyte, facilitating the growth of pie-like Li₂O₂ through a solution mechanism. In-situ electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) experimental data confirm that the discharge products formed under this mechanism exhibit excellent formation and decomposition efficiencies. As a result, the NCO/NP cathode demonstrates an ultra-long cycling performance (719 cycles) and an ultra-low charge-discharge overpotential (0.5 V). Our findings provide a novel strategy for designing high-performance cathodes by manipulating the formation mechanism of Li₂O₂, highlighting the potential of c/a heterostructures in advancing the efficiency and stability of LOBs.