香港城市大学Chunyi Zhi团队报道了水性锌离子电池用空位调制Co3Sn2S2拓扑半金属。相关研究成果发表在2021年10月15日出版的国际学术期刊《德国应用化学》。

拓扑半金属具有较高的导电性和费米能级附近合适的载流子密度，由于其拓扑保护的表面状态，是电化学储能的诱人候选材料。

该文中，研究人员提出了用于水性锌离子电池（AZIBs）的拓扑半金属Co3Sn2S2阴极，显示出接近1.5 V的明显放电平台。通过进一步引入少量Sn空位，与Sn⁴⁺/Sn²⁺的转变对应的额外一对氧化还原峰（1/1.28V）出现。Sn空位导致更多的Zn离子内建通道和活性位点，从而促进电荷储存动力学（zn²⁺扩散速率和电子转移速率），提高Zn离子储存能力。活性中心的增加有助于电容行为的增强。Co3Sn1.8S2阴极在0.2A g^-1下的比能量为394 Wh kg^-1（容量为343.8 mAh g^-1），在5A g^-1下的比功率大于4900 W kg^-1。在1A g^-1下进行2970次循环后，电池的容量保仍持在193.8 mAh g^-1。

由于在较低温度下具有更好的导电性（Co3Sn1.8S2和ZnxCo3Sn1.8S2），制备的准固态Co3Sn1.8S2//Zn电池即使在-30°C（0.6 A/g时为126 mAh g^-1）下也能提供优异的倍率性能，在-10°C温度、2 A/g条件下3000次循环后保持85%的初始容量，具有优异的循环稳定性。

该工作为设计新型电极材料提供了新的见解，通过利用拓扑保护的表面状态，加入空位，并在协同效应中受益匪浅。

附：英文原文

Title: Vacancy Modulating Co3Sn2S2 Topological Semimetal for Aqueous Zinc-Ion Batteries

Author: Yuwei Zhao, Yongbin Zhu, Feng Jiang, Yiyao Li, You Meng, Ying Guo, Qing Li, Zhaodong Huang, Shaoce Zhang, Rong Zhang, Johnny C. Ho, Qianfan Zhang, Weishu Liu, Chunyi Zhi

Issue&Volume: 2021-10-15

Abstract: Topological semimetals with high electrical conductivity and suitable carrier density near Fermi level are enticing candidate materials for electrochemical energy storage meriting from their topologically protected surface states. Here we propose the topological semimetal Co  3  Sn  2  S  2  cathode for aqueous Zn ion batteries (AZIBs) showing an obvious discharge plateau approaching 1.5 V. By further introducing a small amount Sn vacancy, an extra pair of redox peaks (1/1.28 V) appears corresponding to the transition of Sn  4+  /Sn  2+  . Sn vacancy leads to more Zn ion built-in channels and active sites, which promotes charge storage kinetics (Zn  2+  diffusion rate and electron transfer rate) and improves Zn-ion storage capability. The increase of active sites contributes to the enhancement of capacitance behavior. The Co  3  Sn  1.8  S  2  cathode achieves a specific energy of 394 Wh kg  -1  (capacity of 343.8 mAh g  -1  ) at 0.2 A g  -1  and specific power greater than 4900 W kg  -1  at 5 A g  -1  . The battery also retains a capacity of 193.8 mAh g  -1  after 2970 cycles at 1 A g  -1  . Benefited from better conductivity at lower temperatures of Co  3  Sn  1.8  S  2  and Zn  x  Co  3  Sn  1.8  S  2  , the prepared quasi-solid Co  3  Sn  1.8  S  2  //Zn battery delivers superior rate capability even at -30 °C (126 mAh g  -1  at 0.6 A/g) and excellent cycling stability over 3000 cycles retaining 85% of the initial capacity at -10 °C and 2 A/g. This work provides new insights for designing novel electrode materials by leveraging topologically protected surface states, incorporating vacancies, and in synergy benefit a lot.

DOI: 10.1002/anie.202111826

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202111826