Chinese Research Team Achieves Breakthrough in High-Energy Solid-State Lithium Batteries with 451.5 Wh/kg Energy Density

Researchers from the Advanced Carbon and 2D Materials Division at the Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, have made significant progress in high-energy-density solid-state lithium batteries. Addressing the longstanding challenge of balancing plasticizer compatibility and electrochemical stability in polyvinylidene fluoride (PVDF)-based polymer electrolytes, the team proposed a universal fabrication strategy using compatible solvent-assisted plasticization. By introducing a volatile, compatible solvent, the researchers reduced the effective interaction parameter of the mixture, overcoming thermodynamic immiscibility to achieve a homogeneous solution. During film formation, the rapid evaporation of the compatible solvent increased system viscosity, enabling uniform entrapment of electrochemically stable but otherwise incompatible plasticizers—such as sulfolane—within the three-dimensional polymer network. Molecular dynamics simulations and spectroscopic analyses revealed that the copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) interacts with sulfolane via atypical hydrogen bonding. This interaction not only suppresses plasticizer migration and mitigates interfacial side reactions but also reconstructs the solvation structure—dominated by anion aggregates—to form a stable, lithium fluoride-rich interfacial layer, thereby enhancing both cathode and anode interfacial stability. Lithium metal batteries employing this electrolyte paired with a high-voltage nickel-rich cathode (4.7 V) demonstrated exceptional performance, achieving stable cycling for 700 cycles at an ultrahigh rate of 20C (full charge/discharge in ~3 minutes) with a capacity retention of 81.9%. At the pouch-cell level (ampere-hour scale), cells incorporating a thin lithium anode (N/P ratio = 1.1) delivered an energy density of 451.5 Wh/kg after 100 cycles—significantly surpassing that of current commercial lithium iron phosphate (LFP) power cells (~200 Wh/kg)—and passed nail penetration tests, demonstrating excellent intrinsic safety. The findings were published in the *Journal of the American Chemical Society* (*JACS*). The co-first authors are Ruogu Xu, Yujie Wang, and Shengjun Xu; the corresponding authors are Feng Li, Zhenhua Sun, Huiming Cheng, and Yun Tian. This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and the Liaoning Provincial Program for Applied Basic Research.