Molecularly Tailored Lithium–Arene Complex Enables Chemical Prelithiation of High‐Capacity Lithium‐Ion Battery Anodes

• Published in: Angewandte Chemie 2020-08, Vol.132 (34), p.14581-14588
• Main Authors: Jang, Juyoung, Kang, Inyeong, Choi, Jinkwan, Jeong, Hyangsoo, Yi, Kyung‐Woo, Hong, Jihyun, Lee, Minah
• Format: Article
• Language: English
• Subjects: Anodes; arenes; Chemistry; electrochemistry; Flux density; Homogeneity; lithiation; Lithium; Lithium-ion batteries; Mitigation; redox chemistry; Redox potential; Submerging
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202002411

Prelithiation is of great interest to Li‐ion battery manufacturers as a strategy for compensating for the loss of active Li during initial cycling of a battery, which would otherwise degrade its available energy density. Solution‐based chemical prelithiation using a reductive chemical promises unparalleled reaction homogeneity and simplicity. However, the chemicals applied so far cannot dope active Li in Si‐based high‐capacity anodes but merely form solid–electrolyte interphases, leading to only partial mitigation of the cycle irreversibility. Herein, we show that a molecularly engineered Li–arene complex with a sufficiently low redox potential drives active Li accommodation in Si‐based anodes to provide an ideal Li content in a full cell. Fine control over the prelithiation degree and spatial uniformity of active Li throughout the electrodes are achieved by managing time and temperature during immersion, promising both fidelity and low cost of the process for large‐scale integration. LAC of control: A Li–arene complex (LAC) with a redox potential below 0.2 V vs. Li enables chemical prelithiation by Li doping in Si‐based anodes for the first time. The LAC solution allows fine control over the degree of prelithiation to obtain an ideal initial coulombic efficiency as well as spatial uniformity of lithiation, which maximizes the utilization of active materials and energy densities of Li‐ion batteries.