Roll-to-roll prelithiation of Sn foil anode suppresses gassing and enables stable full-cell cycling of lithium ion batteries

• Published in: Energy & environmental science Vol. 12; no. 1; pp. 2991 - 3
• Main Authors: Xu, Hui, Li, Sa, Zhang, Can, Chen, Xinlong, Liu, Wenjian, Zheng, Yuheng, Xie, Yong, Huang, Yunhui, Li, Ju
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2019
• Subjects: Aluminum; Anodes; Cobalt; Cobalt compounds; Electrolytes; Electrolytic cells; Ion transport; Lithium; Lithium-ion batteries; Manganese; Manganese oxides; Metal foils; Nanoparticles; Nickel; Rechargeable batteries; Silicon; Tin dioxide
• DOI: 10.1039/c9ee01404g
• ISSN: 1754-5692

Tin foil should have outstanding volumetric capacity as a Li-ion battery anode; however, it suffers from an unacceptable initial coulombic efficiency (ICE) of 10-20%, which is much poorer than that of Si or SnO 2 nanoparticles. Herein, we demonstrate that bare Sn catalyzes liquid electrolyte decomposition at intermediate voltages to generate gas bubbles and Leidenfrost gas films, which hinder lithium-ion transport and erode the solid-electrolyte interphase (SEI) layer. By metallurgically pre-alloying Li to make Li x Sn foil, the lower initial anode potential simultaneously suppresses gassing and promotes the formation of an adherent passivating SEI. We developed a universally applicable roll-to-roll mechanical prelithiation method and successfully prelithiated Sn foil, Al foil and Si/C anodes. The as-prepared Li x Sn foil exhibited an increased ICE from 20% to 94% and achieved 200 stable cycles in LiFePO 4 //Li x Sn full cells at ∼2.65 mA h cm −2 . Surprisingly, the Li x Sn foil also exhibited excellent air-stability, and its cycling performance sustained slight loss after 12 h exposure to moist air. In addition to LiFePO 4 , the Li x Sn foil cycled well against a lithium nickel cobalt manganese oxide (NMC) cathode (4.3 V and ∼4-5 mA h cm −2 ). The volumetric capacity of the Li x Sn alloy in the LFP//Li x Sn pouch cell was up to ∼650 mA h cm −3 , which is significantly better than that of the graphite anode on a copper collector, with a rate capability as high as 3C. Li x Sn foil anode prepared by mechanical prelithiation suppresses gassing and achieves stable full-cell cycling in lithium ion batteries.