| Ti3C2Tx/MnO2正极在水系锌电池中的电化学性能 | |
| Electrochemical Performance of Ti3C2Tx/MnO2 Cathode in Aqueous Zinc Ion Batteries | |
| 摘要: 二氧化锰(MnO2)材料具有比容量大、电极电位高、储量丰富以及价格低廉等优势，成为水系锌电池正极最受关注的一类材料，然而其仍然存在着结构稳定性差和电化学储存机理复杂的问题。因此，我们通过两步合成法制备了一种花苞状结构的MnO2负载在Ti3C2Tx表面形成Ti3C2Tx/MnO2复合材料，通过X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)对复合样品的结构、成分和形貌进行表征。通过将Ti3C2Tx/MnO2复合材料作为正极，与锌负极匹配组装成水系锌电池，研究了其分别在2 mol·L-1 ZnSO4、2 mol·L-1 ZnSO4+0.1 mol·L-1 MnSO4、30 mol·L-1三氟甲基磺酸四乙基铵(TEAOTf)+1 mol·L-1三氟甲烷磺酸锌(ZnOTf)和3 mol·L-1 ZnOTf四种电解液中的电化学性能。结果表明，Ti3C2Tx/MnO2在2 mol·L-1 ZnSO4中的比容量较高，但循环稳定性很差。将TEAOTf盐和ZnOTf盐共溶于水中，设计了一种新型的含惰性阳离子的超高浓度盐包水电解液(30 mol·L-1 TEAOTf+1 mol·L-1 ZnOTf)，不仅提高了Ti3C2Tx/MnO2材料的可逆性，而且有效抑制了电极材料在循环过程中的溶解。 | |
| 关键词: 水系锌电池 Ti3C2Tx/MnO2 电化学性能 三氟甲基磺酸四乙基铵 三氟甲烷磺酸锌 | |
| 基金项目: 国家自然科学基金(No.22072068)资助。 | |
| Abstract: Owing to the advantages of large specific capacity, high work potential, rich reserves, and low price, manganese dioxide (MnO2) material has become the most potential material for the cathode in aqueous zinc batteries (AZBs). However, it still has problems with poor structural stability and complex electrochemical storage mechanism. Herein, a kind of Ti3C2Tx/MnO2 composite material based on bract-liked structural of MnO2 deposited on Ti3C2Tx was prepared by a two-step method, and the structure, composition, and morphology of the composite were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The zinc storage performance of Ti3C2Tx/MnO2 cathode were evaluated in different aqueous electrolyte (2 mol·L-1 ZnSO4, 2 mol·L-1 ZnSO4+0.1mol·L-1 MnSO4, 30 mol·L-1 tetraethylammonium triflate (TEAOTf)+1 mol·L-1 ZnCF3SO3 (ZnOTf), 3 mol·L-1 ZnOTf), respectively. As a result, Ti3C2Tx/MnO2 cathode displayed two obvious discharge platforms in 2 mol·L-1 ZnSO4 and 2 mol·L-1 ZnSO4+0.1 mol·L-1 MnSO4 solution, which is attributed to the co-insertion of H+ and Zn2+ due to the weak acidic electrolyte. The initial platform region at 1.0 V occurred in the first step is the insertion of H+, and the subsequent reaction is the insertion of Zn2+ into Ti3C2Tx/MnO2 electrode. However, in the neutral of 3 mol·L-1 ZnOTf and 30 mol·L-1 TEAOTf+1 mol·L-1 ZnOTf electrolyte, the insertion of H+ into the Ti3C2Tx/MnO2 cathode hardly appears, and the obtained discharge capacity may mainly come from the intercalation of Zn2+. Moreover, the utilization of ultra-high concentration electrolyte could not only improve the reversibility of Ti3C2Tx/MnO2 electrode material but also effectively inhibit the dissolution of electrode material in the cycling process (78.2% capacity retention after 100 cycles at 0.2 A·g-1). | |
| Keywords: aqueous zinc battery Ti3C2Tx/MnO2 electrochemical performance tetraethylammonium triflate ZnCF3SO3 | |
| 投稿时间：2021-09-27 修订日期：2022-02-18 | |
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| 杨贝贝,杜妍妍,张宇霖,陈婷婷,宾端,陆洪彬,夏永姚.Ti3C2Tx/MnO2正极在水系锌电池中的电化学性能[J].无机化学学报,2022,38(4):578-588. | |
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