Cell Design and Materials: Li-Ion

Lithium Metal History - The Progenitor of Lithium-Ion Lithium metal anodes have a long history as one of the first materials used in rechargeable batteries, offering a high theoretical capacity 3,862 mAh/g) and low electrochemical potential, making them attractive for high-energy applications. Foundational lithium-metal research began in the early 1970s at Exxon, where M. Stanley Whittingham demonstrated the first rechargeable lithium-metal/titanium disulfide TiS2 cell2, ushering in the modern era of high-energy battery chemistries. Lithium metalʼs promise was clear: far higher energy density and dramatically longer shelf life than nickel-cadmium cells, which typically lasted only months. However, by the 1980s it became evident that lithium-metal anodes suffered from dendritic growth during cycling1. These dendrites could penetrate separators and cause internal short circuits, posing significant risks and making the chemistry difficult to commercialize. In 1977, Canadian company Moli Energy became the first company to bring rechargeable lithium-metal batteries to market, but high-profile safety failures in 1989, resulting in recalls, highlighted the unresolved dendrite problem and ended large-scale commercial efforts for decades to come.1 As a result, the development of lithium-ion batteries, which use graphite anodes, gained momentum in the 1990s. While graphite offers lower energy density 372 mAh/g), its stability, safety, and longevity made it the standard for commercial applications, enabling the widespread adoption of portable electronics and electric vehicles EVs. In recent years, interest in lithium metal anodes has resurged due to the growing demand for batteries with higher energy density for eVTOLs, drones, and aerospace applications. Research continues to examine ways to address existing challenges associated with lithium-metal, including dendrite formation, interface instability, and limited cycle life. Approaches under study include solid-state and hybrid electrolytes, protective interfacial layers, electrolyte additives, and engineered separators, all aimed at improving plating uniformity and enhancing stability during cycling. While lithium-metal remains a promising candidate for next-generation systems, including solid-state and lithium-sulfur batteries, its practical adoption depends on resolving these technical issues and demonstrating reliable performance under application-relevant conditions. Source: 1 Moli Energy, 2 Research at Exxon, 3 Lithium Metal Anodes in Solid-State Batteries, 4 Battery Report 2023 and 2024

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