Li2ZnTi3O8/C anode with high initial Coulombic efficiency, long cyclic life and outstanding rate properties enabled by fulvic acid

• Published in: Carbon (New York) 2020-08, Vol.163, p.297-307
• Main Authors: Qin, Jia-Li, Zhu, Hui-Ling, Lun, Ning, Qi, Yong-Xin, Bai, Yu-Jun
• Format: Article
• Language: English
• Subjects: Anodes; Batteries; Carbon; Carbon fibers; Cyclability; Electrochemical analysis; Electrode materials; Electrolytes; Electron transfer; Fulvic acid; Initial Coulombic efficiency; Ion diffusion; Ion migration; Li2ZnTi3O8; Lithium; Lithium-ion batteries; Molten salt electrolytes; Rate capability; Rechargeable batteries; Solid electrolytes; Studies
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2020.03.029

Industrialized anode materials for Li-ion batteries (LIBs) require high initial Coulombic efficiency (ICE), long cyclic life and outstanding rate properties. Herein, fulvic acid (FA) with the elements of C, H, O, N and S was adopted as the carbon precursor to mix with Li2ZnTi3O8 (LZTO) followed by carbonizing to optimize the electrochemical performance of the LZTO anode. At a weight ratio of 0.28 for FA/LZTO, the product carbonized at 800 °C reveals high ICE of 88.0%, remarkable rate capabilities (lithiation/delithiation capacities of 195.4/191 and 143.5/143.5 mAh g−1 at 0.1 and 1.6 A g−1, respectively). After undergoing 1000 cycles at 0.5 A g−1, the retained reversible capacity is 215.3 mAh g−1. The excellent performance suitable for industrial power LIBs associates with the N and S co-doped discontinuous carbon coating layers, small carbon bumps and membranes on the LZTO particle surface. The carbon material facilitates electron transfer and the exposed LZTO surface maintains the good Li-ion migration of LZTO. Particularly, the NO3− radicals yielded favor to boost the Li-ion diffusion by transforming into the solid state electrolytes of Li3N and LiNxOy in the lithiation process. [Display omitted]