Liu Tingting, Wu Han, Du Xiaofan, Wang Jinzhi, Chen Zheng, Wang Hao, Sun Jinran, Zhang Jianjun, Niu Jiaping, Yao Lishan, Zhao Jingwen, Cui Guanglei
Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P. R. China.
School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
ACS Appl Mater Interfaces. 2022 Jul 27;14(29):33041-33051. doi: 10.1021/acsami.2c04893. Epub 2022 Jul 18.
Aqueous sodium batteries are one of the awaited technologies for large-scale energy storage, but remain poorly rechargeable because of the reactivity issues of water. Here, we present a hydrated eutectic electrolyte featuring a water-locked effect, which is exceptional in that the O-H bond of water is essentially strengthened via weak hydrogen bonding (relative to the original HO-HO hydrogen bonds) to low-donor-number anions and ligands. Even without interphase protection, both the anodic and cathodic water electrodecomposition reactions are delayed, extending the aqueous potential window to 3.4 V. Combined with the alleviated electrode dissolution, NaMnFe(CN)||NaTi(PO) batteries deliver a high energy density of ∼80 W h kg at 0.5 C and undergo over 1000 cycles with a 74.5% capacity retention and a 99.4% Coulombic efficiency at 4.2 C. This work may offer a general guide to ultimately exploit the water's innate stability for realizing the promise of aqueous battery technologies.
水系钠电池是大规模储能领域备受期待的技术之一，但由于水的反应活性问题，其充电性能仍然较差。在此，我们展示了一种具有水锁定效应的水合共晶电解质，其独特之处在于，通过与低给体数阴离子和配体形成弱氢键（相对于原始的HO-HO氢键），水的O-H键得到了实质性增强。即使没有界面保护，阳极和阴极的水电解反应也会延迟，将水系电池的电势窗口扩展到3.4V。结合减轻的电极溶解，NaMnFe(CN)||NaTi(PO)电池在0.5C时可提供约80Wh kg的高能量密度，并在4.2C下经历超过1000次循环，容量保持率为74.5%，库仑效率为99.4%。这项工作可能为最终利用水的固有稳定性以实现水系电池技术的前景提供一个通用指南。
