Anion-Trap Engineering toward Remarkable Crystallographic Reorientation and Efficient Cation Migration of Zn Ion Batteries

作者：Qiu, Meijia; Sun, Peng; Wang, Yu; Ma, Liang; Zhi, Chunyi^*; Mai, Wenjie^*

来源：Angewandte Chemie - International Edition, 2022, 61(44): e202210979.

DOI：10.1002/anie.202210979

• Anion-Trap
• Crystallographic Reorientation
• Efficient Cation Migration
• Zn Ion Batteries

Zn batteries are considered as potential candidates in future power sources, however suffer problems of rampant dendrite/by-product on Zn anodes, torpid Zn2+ transfer/diffusion and poor energy density. Inspired by the host-guest interaction chemistry, an anion-trap agent beta-cyclodextrin (beta-CD) is introduced into the Zn(ClO4)(2) electrolyte to induce dominant Zn (002) deposition and improve Zn2+ migration behaviors. The anion ClO4- is revealed to be trapped inside the cavity of beta-CD, impairing barriers for Zn2+ migration and significantly elevating the Zn2+ transference number to 0.878. Meanwhile, the beta-CD@ClO4- complex shows the function in preferential growth of the Zn (002), blocking the approach of dendrite growth. Above combined functions lead to substantial enhancement in long-term stability and cell capacity, as proved by 10 times longer life of Zn parallel to Zn symmetric cells and 57 % capacity increasement of Zn-MnO2 full cells (at 0.1 A g(-1)) compared with that of pure Zn(ClO4)(2) electrolyte.