Li Xinliang, Li Na, Huang Zhaodong, Chen Ze, Liang Guojin, Yang Qi, Li Mian, Zhao Yuwei, Ma Longtao, Dong Binbin, Huang Qing, Fan Jun, Zhi Chunyi
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China.
Qianwan Institute of CNiTECH, Zhongchuangyi Road, Hangzhou bay District, Ningbo, Zhejiang, 315336, China.
Adv Mater. 2021 Feb;33(8):e2006897. doi: 10.1002/adma.202006897. Epub 2021 Jan 20.
Weak binding and affinity between the conductive support and iodine species leads to inadequate electron transfer and the shuttle effect. Herein, redox kinetics and duration are significantly boosted by introducing a Nb CT host that is classified as a layered 2D Nb-based MXene. With a facile electrodeposition strategy, initial I ions are electrically driven to insert in the nanosized interlayers and are electro-oxidized in situ. Linear I is firmly confined inside and benefits from the rapid charge supply from the MXene. Consequently, an aqueous Zn battery based on a Zn metal anode and ZnSO electrolyte delivers an ultraflat plateau at 1.3 V, which contributes to 84.5% of the capacity and 89.1% of the energy density. Record rate capability (143 mAh g at 18 A g ) and lifespan (23 000) cycles are achieved, which are far superior to those of all reported aqueous MXenes and I -metal batteries. Moreover, the low voltage decay rate of 5.6 mV h indicates its superior anti-self-discharge properties. Physicochemical analyses and density functional theory calculations elucidate that the localized electron transfer and trapping effect of the Nb CT MXene host are responsible for enhanced kinetics and suppressed shuttle behavior. This work can be extended to the fabrication of other I -metal batteries with long-life-time expectations.
导电载体与碘物种之间的弱结合力和亲和力会导致电子转移不足和穿梭效应。在此，通过引入一种被归类为层状二维铌基MXene的Nb CT主体，氧化还原动力学和持续时间得到了显著提升。采用简便的电沉积策略，初始碘离子被电驱动插入纳米级夹层中并原位电氧化。线性碘被牢固地限制在内部，并受益于MXene的快速电荷供应。因此，基于锌金属阳极和硫酸锌电解质的水系锌电池在1.3 V时提供超平坦的平台，这占容量的84.5%和能量密度的89.1%。实现了创纪录的倍率性能（在18 A g时为143 mAh g）和寿命（23000次）循环，远远优于所有已报道的水系MXene和碘-金属电池。此外，5.6 mV h的低电压衰减率表明其具有优异的抗自放电性能。物理化学分析和密度泛函理论计算表明，Nb CT MXene主体的局部电子转移和俘获效应是动力学增强和穿梭行为抑制的原因。这项工作可以扩展到制造其他具有长寿命预期的碘-金属电池。
