Unsymmetrical fluorinated malonatoborate as an amphoteric additive for high-energy-density lithium-ion batteries

Citation data:

Energy & Environmental Science, ISSN: 1754-5692, Vol: 11, Issue: 6, Page: 1552-1562

Publication Year:
Mentions 1
News Mentions 1
Repository URL:
Han, Jung-Gu; Lee, Jae Bin; Cha, Aming; Lee, Tae Kyung; Cho, Woongrae; Chae, Sujong; Kang, Seok Ju; Kwak, Sang Kyu; Cho, Jaephil; Hong, Sung You; Choi, Nam-Soon Show More Hide
Royal Society of Chemistry (RSC); ROYAL SOC CHEMISTRY
Environmental Science; Energy
Most Recent News Mention
article description
High-capacity Si-embedded anodes and Li-rich cathodes are considered key compartments for post lithium-ion batteries with high energy densities. However, the significant volume changes of Si and the irreversible phase transformation of Li-rich cathodes prevent their practical application. Here we report lithium fluoromalonato(difluoro)borate (LiFMDFB) as an unusual dual-function additive to resolve these structural instability issues of the electrodes. This molecularly engineered borate additive protects the Li-rich cathode by generating a stable cathode electrolyte interphase (CEI) while simultaneously tuning the fluoroethylene carbonate (FEC)-oriented solid electrolyte interphase (SEI) on the Si-graphite composite (SGC) anode. The complementary electrolyte design utilizing both LiFMDFB and FEC exhibited an improved capacity retention of 85%, a high Coulombic efficiency of ∼99.5%, and an excellent energy density of ∼400 W h kgin Li-rich/SGC full cells at a practical mass loading after 100 cycles. This dual-function additive approach offers a way to develop electrolyte additives to build a more favorable SEI for high-capacity electrodes.