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A high-volumetric-capacity and high-areal-capacity ZnCo₂O₄ anode for Li-ion batteries enabled by a robust biopolymer binder

Liu, Jie, Xuan, Yuxue, Galpaya, Dilini G. D., Gu, Yuanxiang, Lin, Zhan, Zhang, Shanqing, Yan, Cheng, Feng, Shouhua, Wang, Lei
Journal of materials chemistry 2018 v.6 no.40 pp. 19455-19462
anodes, biopolymers, chemistry, guar gum, lithium batteries, mechanical properties, thermoplastics
Constructing high-areal-capacity anodes with high loading for Li-ion batteries is still an enormous challenge, due to the drastic volume change of large-capacity anode materials during cycling. The conventional PVDF binder system fails to withstand the degradation of high-loading electrodes. Therefore, advanced binders are urgently required. Herein, for the first time, the guar gum (GG) biopolymer has been exploited as a robust binder for micro-sized ZnCo₂O₄ (ZCO) anode materials. Because of its robust mechanical properties and strong interactions with ZCO, the cycling stability of the ZCO anode has been significantly improved with a capacity of 412 mA h g⁻¹ after 600 cycles at 1200 mA g⁻¹. More importantly, the ZCO can act as a “crosslinking agent” to in situ form a robust network with GG, which efficiently maintains the electrode structure stability. Hence, a ZCO anode with an ultrahigh loading of 6.73 mg cm⁻² can be achieved and deliver a high areal capacity of 5.6 mA h cm⁻². Simultaneously, benefiting from the high tap density of micro-ZCO, the ZCO anode gives a high volumetric capacity of 1179 mA h cm⁻³. This study will make a significant contribution to accelerating the progress of designing high-areal-capacity anodes.