南开大学程方益团队报道了超分子环糊精添加剂促进Zn阳极在水电解质中的动力学和稳定性。相关研究成果于2022年6月14日发表在国际顶尖学术期刊《美国化学会杂志》。

环糊精（CDs）具有疏水性内腔和亲水性外表面，具有广阔的电化学应用前景。

该文中，研究人员报告了镉分子（α-镉、β-镉和γ-镉）作为可充电锌电池电解质添加剂的比较和机理研究。在ZnSO₄水溶液中加入α-CD可降低镀锌层的成核过电位和活化能，抑制H₂生成。计算、光谱和电化学研究表明，α-CD优先通过次生羟基平行吸附在Zn表面，抑制了水诱导的析氢副反应和氢氧化物硫酸盐的形成。

此外，具有强电子密度的α-CD的亲水外表面同时促进了Zn²⁺的沉积，并减轻了Zn枝晶的形成。配制的3M ZnSO₄+10 mMα-CD电解液能够在1 mA cm^–2的Zn | Cu电池中实现均匀的镀锌/剥离（平均库仑效率～99.90%），并且在Zn | V₂O₅全电池中进行800次循环后可保持84.20%的容量。

该研究为利用超分子大环调节和增强水电池化学中金属阳极的界面稳定性和动力学提供了深入的见解。

附：英文原文

Title: Boosting the Kinetics and Stability of Zn Anodes in Aqueous Electrolytes with Supramolecular Cyclodextrin Additives

Author: Kang Zhao, Guilan Fan, Jiuding Liu, Fangming Liu, Jinhan Li, Xunzhu Zhou, Youxuan Ni, Meng Yu, Ying-Ming Zhang, Hui Su, Qinghua Liu, Fangyi Cheng

Issue&Volume: June 14, 2022

Abstract: The hydrophobic internal cavity and hydrophilic external surface of cyclodextrins (CDs) render promising electrochemical applications. Here, we report a comparative and mechanistic study on the use of CD molecules (α-, β-, and γ-CD) as electrolyte additives for rechargeable Zn batteries. The addition of α-CD in aqueous ZnSO4 solution reduces nucleation overpotential and activation energy of Zn plating and suppresses H2 generation. Computational, spectroscopic, and electrochemical studies reveal that α-CD preferentially adsorbs in parallel on the Zn surface via secondary hydroxyl groups, suppressing water-induced side reactions of hydrogen evolution and hydroxide sulfate formation. Additionally, the hydrophilic exterior surface of α-CD with intense electron density simultaneously facilitates Zn2+ deposition and alleviates Zn dendrite formation. A formulated 3 M ZnSO4 + 10 mM α-CD electrolyte enables homogenous Zn plating/stripping (average Coulombic efficiency ～ 99.90%) at 1 mA cm–2 in Zn|Cu cells and a considerable capacity retention of 84.20% after 800 cycles in Zn|V2O5 full batteries. This study provides insight into the use of supramolecular macrocycles to modulate and enhance the interface stability and kinetics of metallic anodes for aqueous battery chemistry.

DOI: 10.1021/jacs.2c00551

Source: https://pubs.acs.org/doi/10.1021/jacs.2c00551