Research on the influence of Li+ contents on the electrochemical hydrogen storage properties of BaCe1-xLixO3 solid solutions

The development of nickel-metal hydride battery anodes has long been limited by the inherent capacity decay of the anodes of the metal alloy materials. In this study, the BaCe 1-x Li x O 3 solid solutions with controlled contents of Li +  ions (x = 0–0.8) were synthesized via combustion method and adopted them as the novel negative materials to offer a breakthrough in overcoming traditional performance constraints. The influences of Li + contents on microstructure and electrochemical hydrogen storage performance were systematically investigated. X-ray Diffraction test (XRD) confirmed that the Li +  ions were successfully incorporated into the BaCeO 3 lattice and substituted at the Ce 4+ sites. The grain sizes were gradually decreased from 73.5 nm (undoped) to 67.0 nm (Li 0.08 ). Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) results further supported the reduction of the grain sizes and proved that the Li +  ions had doped into the lattice of the BaCeO 3 . Spectral tests showed that the Li +  ions induced obvious changes in the lattice structures and the concentration of oxygen vacancies. Electrochemical hydrogen storage performance tests demonstrated that the discharge capacity of BaCe 0.96 Li 0.04 O 3 achieved 212.7 mAh/g, representing 95.1 % improvement over the undoped sample (109.0 mAh/g), along with higher charge retention. Kinetic analysis further confirmed the superior hydrogen storage kinetic behavior of the doped samples. These results fully proved that the doping of Li +  ions can effectively enhance the hydrogen storage performances of BaCeO 3 materials.