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.
Irreversible capacity loss during the initial charge–discharge process poses a significant challenge to the practical application of high-theoretical-capacity anodes in lithium-ion batteries. Therefore, prelithiation technology has emerged as a pivotal choice for the advancement of high-energy-density lithium-ion batteries. Herein, we introduce a bilayer coating strategy with Li2S-polyacrylonitrile (Li2S-PAN) as the prelithiation source. Specifically, Li2S-PAN can selectively release active lithium ions during the initial charge process with a specific capacity of 695 mAh g–1. When integrated into a LiFePO4 cathode, Li2S-PAN can achieve a 48.2% additional capacity. Furthermore, the LiFePO4|SiC full cell exhibits a ∼20.0% initial lithium compensation with the reversible capacity increasing from 101 to 121 mAh g–1. Overall, this work proposes a facile and scalable route for the future application of high-theoretical-capacity anodes (silicon, tin, etc.) in the lithium-ion battery industry.
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