Li5FeO4 Li Source Additive Fixing Irreversibility in Li-Ion Batteries

Abstract

The initial irreversible capacity loss (ICL) in Li-ion batteries (LIB) occurs at both the anode and cathode materials. For the cathode, mostly interfacial losses are seen. However, the anode is typically more severe due to the creation of the solid-electrolyte interphase or SEI that consumes lithium in the cell on the first cycle, that passivates the carbon (graphite) electrode surface that enables further cycling at decent energy and coulombic efficiencies. However deleterious lithium consuming reactions continue to occur; caused by other reasons, such as decomposition of electrode materials, electrolyte additives, or side reactions that are not beneficial but all consuming. As a result, the number of lithium-ions available in the cell for cycling is decreased, leading to unmitigated decrease of the cell capacity and energy content. In this study, advanced high-performance lithium-ion cells and batteries that contain high-lithium-content additives such as Li5FeO4 or ‘LFO’ are used in the LIBs. Such additives improve the lithium-ion cell by electrochemically releasing large quantities of sacrificial lithium on the first formation cycle to treat too large irreversible capacity losses (ICL) (Figure 1). Additional benefits also include improved cycle-over-cycle coulombic efficiency in such cells. These solid powder oxide-based lithium-containing additives are enabled by co-blending with an active material cathode (e.g.; nickel manganese cobalt, NMC, or lithium cobalt oxide, LCO, or nickel cobalt aluminum or NCA) into an electrode in an as-prepared state. Such co-blended cathodes, when properly cell-balanced and thus paired with high-capacity and high energy/capacity containing advanced anode electrodes such as silicon, silicon oxide, or tin-containing intermetallic alloys, or high-capacity hard carbons, and graphite anodes thus results in a higher energy dense lithium-ion cell than previous state-of-art. Figure 1. Voltage profiles of various LIB materials including Li-source additive Li5FeO4. Acknowledgements This work is supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This work was supported as part of the Center for Electrochemical Energy Science (CEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. Figure 1