A Scalable Cathode Chemical Prelithiation Strategy for Advanced Silicon-Based Lithium Ion Full Batteries.

Abstract

A silicon anode with ultra-high specific capacity has motivated tremendous exploration for high-energy-density lithium ion batteries while it still faces serious issues of irreversible lithium loss, unstable electrode electrolyte interface (SEI), and huge volume expansion. Prelithiation is a crucial technology to alleviate the harm of active lithium loss of silicon-based full-cell systems. Herein, we reported a cathode prelithiation method using Li2S-PAN as a lithium "donor", which was synthesized via chemical reaction between sulfurized polyacrylonitrile and Li-biphenyl complex. The Li2S-PAN with an initial charging capacity of 668 mAh g-1 (2.5-4.0 V) is loaded on the LiFePO4 electrode, and the LiFePO4/Li2S-PAN composite electrode displays a high initial charge capacity of 206 mAh g-1, which is 22.3% higher than the pristine LiFePO4. With a silicon/graphite/carbon (Si/G/C) composite anode, the Si/G/C||LiFePO4/Li2S-PAN full cell exhibits a reversible capacity of 123 and 107 mAh g-1 in the 1st and 10th cycle, which is 15.5 and 24.5% higher than the Si/G/C||LiFePO4 battery, respectively. The SEI layer of the silicon anode in the Si/G/C||LiFePO4/Li2S-PAN cell contains abundant conductive LiF species, which can enhance the interfacial stability and reaction kinetics of the cells. The proposed cathode prelithiation process is compatible with the industrial roll-to-roll electrode preparation process, exhibiting a promising application prospect.