Lithium (Li) metal stands out as the most promising anode material due to its exceptionally low redox potential (–3.04 V vs. standard hydrogen electrode) and the remarkable theoretical capacity (3860 mAh·g^–1). Nevertheless, unlimited volume expansion, and the fragility of the solid-electrolyte-interphase (SEI) often lead to the formation of lithium dendrites and inactive “dead lithium”, resulting in persistent capacity degradation, low Coulombic efficiency (CE) and significant safety risks for lithium metal batteries.

The jointed research by Prof. Guojie Li of Zhengzhou University, Prof. Aoxuan Wang of Tianjin University, Prof. Qibo Deng of Hebei University of Technology and the co-workers found a method to solve the above problem by creating a stable Al-Li/LiF artificial interphase into lithium metal batteries. This study is published online in https://doi.org/10.1007/s11705-025-2539-0.

“Firstly, a stable Al-Li/LiF artificial interphase (LAF) with rapid ion transport pathways is created through a one-step chemical pretreatment process.” Prof. Wang said. “As the artificially generated LiF and Al-Li alloy artificial SEI can eliminate dead lithium and lithium dendrites, deposit lithium in the lower section of the modified interface by promoting ion transport, strengthening the mechanical properties, electrolyte wettability, cycling stability and capacity retention.”

In a two-step study, the researchers first examine the morphologies, chemical composition, physical properties and so on to confirm the successful synthesis of the Al-Li/LiF artificial interphase, illustrating the Al and F elements uniform distribution in the surface layer, forming a beneficial aluminum-lithium alloy (Li₉Al₄) and LiF. The batteries exhibit the excellent profermance and the research promots the further application into industry.

Using a serious of LAF||LFP full cell containing varied Al-Li/LiF artificial interphase Al have been constructed, the researchers has completed the electrochemical properties. The LAF-20||LFP full cell exhibited remarkable cycle stability, delivering a discharge capacity of 114.3 mAh·g^–1 after 300 cycles and a capacity retention rate of 75.5%. Then, to gain insight into the mechanism, the chemical constitution and morphologies after cycling after 100 cycles had also been done carefully.

“Our research shows that 20 μm of the LAF is the most appropriate modification layer thickness.” said Qibo Deng, the co-corresponding author of the study come from Hebei University of Technology. “This hybrid artificial SEI exhibits high ion conductivity, low electron conductivity, and excellent mechanical properties. It effectively inhibits side reactions between the lithium anode and electrolyte, as well as the growth of lithium dendrites, while allowing for rapid lithium ion transport and deposition beneath it.”
DOI: 10.1007/s11705-025-2539-0