A salt-free medium facilitating electrode prelithiation towards fast-charging and high-energy lithium-ion batteries

The substantial consumption of lithium ions and sluggish reaction kinetics at the anode detrimentally impact the deliverable energy and fast-charging capability of lithium-ion batteries with silicon-based anodes. The prevailing contact prelithiation method using an electrolyte medium can replenish the active lithium, but it may cause materials/electrode instability and bring barrier for lithium-ion transport. Here we explore a contact prelithiation methodology employing cyclic carbonate mediums that can enable spatially and temporally uniform prelithiation reaction. These mediums enable a delicate equilibrium between a lithium-ion diffusion and the intrinsic prelithiation reaction rate throughout the electrode depth. Not only does this prelithiation method serve the fundamental purpose of tackling lithium loss issue, but it also fosters the creation of a solid electrolyte interphase with favorable lithium-ion transport properties. By utilizing fluoroethylene carbonate as the medium for anode contact prelithiation, an Ah-level laminated Si/C||LiCoO₂ pouch cell shows a significant enhancement in cell-level energy density by 42.7%. Moreover, a Si/C||LiCoO₂ pouch cell achieves an 80.9% capacity utilization at a fast-charging rate of 10 C (6 min) and exhibits a low capacity decay rate of 0.047% per cycle. Such a prelithiation method demonstrates versatility across various cyclic carbonate mediums, electrodes, and scalability for industrial applications.