Recently, Southeast University, in partnership with the Institute of Physics at the Chinese Academy of Sciences, has released a research paper in the esteemed Angewandte Chemie International Edition. This groundbreaking study introduces an innovative approach known as current collector-driven oxygen vacancy gradient engineering. By employing platinum as the current collector and capitalizing on its oxygen adsorption capabilities, the researchers successfully constructed an oxygen vacancy gradient in situ during the deposition of vanadium oxide thin films. This gradient features a concentration that increases from the surface inward. Such a gradient structure opens up additional channels for lithium-ion diffusion, lowers the ion diffusion barrier, and overcomes the traditional challenge of uneven lithium diffusion in pre-lithiation processes. As a result, it enables deep and uniform in-situ pre-lithiation.

Experimental results showcase that the oxygen vacancy gradient facilitates thorough lithium-ion penetration to the current collector interface, markedly enhancing the uniformity of lithium distribution. The all-solid-state thin-film battery assembled through this method achieves a first-cycle Coulombic efficiency of 76.5%, an areal capacity of 37.5 μAh cm⁻² within a thick electrode system, and maintains a capacity retention rate of 91.5% after 2,000 cycles. These performance metrics position the battery among the top performers in its class.

This novel strategy effectively tackles issues prevalent in traditional pre-lithiation, such as low efficiency, inconsistent lithium distribution, and significant interfacial side reactions. It offers a straightforward and scalable technical solution for the development of high-performance all-solid-state thin-film lithium batteries. Furthermore, it advances the research and application of high-energy-density, long-life solid-state power sources tailored for microelectronic devices.