It encompassed a complete cell configuration that combined LiFePO4 (LFP) with ZDDP-coated lithium, demonstrating outstanding cycling durability with a 83.2% capacity retention after 350 cycles.
A group of researchers led by scientists from Central South University in Changsha, Hunan, China, has harnessed the capabilities of the Australian Synchrotron to pioneer an innovative approach to produce thin, high-performance, standalone lithium anodes for lithium-ion batteries. This advancement dramatically enhances cycling stability and electrochemical properties, addressing the growing demand for top-tier lithium-ion batteries. Solid-state lithium metal, with its theoretically high energy density and capacity, presents an attractive alternative to traditional graphite anodes.The research team revealed that they achieved improved performance in thin lithium metal strips by incorporating a special zinc additive known as dialkyl dithiophosphate (ZDDP). This additive had several beneficial effects: it bolstered the hardness at the interface, thwarted structural deterioration (preventing the growth of lithium dendrites), regulated the deposition of lithium during plating and stripping processes, and enabled faster plating and stripping of the lithium anode compared to other materials. The team successfully produced thin lithium strips spanning thicknesses from 5 to 50 micrometers, showcasing superior mechanical strength, electrochemical performance, and remarkable cycling stability when compared to untreated lithium strips. Even at high area capacities, these treated lithium strips maintained a cycle lifetime of up to 2,800 hours. Furthermore, a symmetrical cell built using ultrathin lithium strips measuring 15 micrometers in thickness endured for over 800 hours. In contrast, a cell lacking ZDDP exhibited rapid degradation.The enhanced electrochemical properties of the ZDDP-coated lithium anode were attributed to the formation of a robust artificial solid electrolyte interface (SEI) layer with a strong affinity for lithium. Dr. Bernt Johannessen, the instrument scientist involved in this work, highlighted it as a noteworthy example of pioneering efforts in the development of ultra-thin lithium, with thicknesses measured in microns, engineered explicitly for solid-state batteries. The production process involved the use of a zinc-based oil, which allowed for the gradual reduction of lithium thickness, similar to rolling dough through a pasta machine. Samples were sent to the synchrotron for analysis, and scientists conducted measurements of the lithium anodes using the X-ray absorption spectroscopy beamline, a particularly valuable tool for investigating energy materials and catalysis.
