Investigation of Pre-lithiation in Graphite and Hard-Carbon Anodes Using Different Lithium Source Structures

Abstract

Energy storage devices like batteries and supercapacitors, have become indispensable in portable devices and electric vehicles. But, the carbon anodes used in these devices, exhibit a significant loss in their initial capacity (graphite: 6.6% and hard carbon: 29.8%) due to the consumption of Li ions from electrolyte during solid electrolyte interface layer formation and other non-reversible reactions, and if unaddressed, can potentially diminish this advantage. Pre-lithiation treatment of carbon anodes can mitigate this loss, apart from improving the cell working potential, hence enhancing cell energy density and cyclability. We investigate in this report a direct-contact lithiation process in graphite and hard carbon anodes using four distinct lithium source structures. The results show that the type of Li-source structure employed for anode pre-lithiation can have a major impact on the electrode physical properties, pre-lithiation times and the pre-lithiation anode potentials achieved, potentially effecting the SEI properties, cycle life, and the electrode processing costs.