Ti_(3)C_(2)T_(x)/MnO_(2)正极在水系锌电池中的电化学性能  

Electrochemical Performance of Ti_(3)C_(2)T_(x)/MnO_(2) Cathode in Aqueous Zinc Ion Batteries

作　　者：杨贝贝 杜妍妍 张宇霖 陈婷婷[1] 宾端 陆洪彬 夏永姚[3] YANG Bei-Bei;DU Yan-Yan;ZHANG Yu-Lin;CHEN Ting-Ting;BIN Duan;LU Hong-Bin;XIA Yong-Yao(Department of Chemistry and Chemical Engineering,Nantong University,Nantong,Jiangsu 226019,China;Haian Institute of High-Tech Research,Nanjing University,Nantong,Jiangsu 226634,China;Department of Chemistry,Fudan University,Shanghai 200433,China)

机构地区：[1]南通大学化学化工学院,南通226019 [2]南京大学海安高新技术研究院,南通226634 [3]复旦大学化学系,上海200433

出　　处：《无机化学学报》2022年第4期578-588,共11页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.22072068)资助。

摘　　要：二氧化锰(MnO_(2))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MnO_(2)负载在Ti_(3)C_(2)T_(x)表面形成Ti_(3)C_(2)T_(x)/MnO_(2)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Ti_(3)C_(2)T_(x)/MnO_(2)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) ZnSO_(4)、2 mol·L^(-1) ZnSO_(4)+0.1 mol·L^(-1) MnSO_(4)、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,Ti_(3)C_(2)T_(x)/MnO_(2)在2 mol·L^(-1) ZnSO_(4)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Ti_(3)C_(2)T_(x)/MnO_(2)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。Owing to the advantages of large specific capacity,high work potential,rich reserves,and low price,man⁃ganese dioxide(MnO_(2))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 Ti_(3)C_(2)T_(x)/MnO_(2) composite material based on bract⁃liked structural of MnO_(2) deposited on Ti_(3)C_(2)T_(x) 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 Ti_(3)C_(2)T_(x)/MnO_(2) cathode were evaluated in different aqueous electrolyte(2 mol·L^(-1) ZnSO_(4),2 mol·L^(-1) ZnSO_(4)+0.1 mol·L^(-1) MnSO_(4),30 mol·L^(-1) tetraethylammonium triflate(TEAOTf)+1 mol·L^(-1) ZnCF3SO3(ZnOTf),3 mol·L^(-1) ZnOTf),respectively.As a result,Ti_(3)C_(2)T_(x)/MnO_(2) cathode displayed two obvious discharge platforms in 2 mol·L^(-1) ZnSO_(4) and 2 mol·L^(-1) ZnSO_(4)+0.1 mol·L^(-1) MnSO_(4) solution,which is attributed to the co⁃insertion of H+and Zn^(2+)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 subse⁃quent reaction is the insertion of Zn^(2+)into Ti_(3)C_(2)T_(x)/MnO_(2) 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 Ti_(3)C_(2)T_(x)/MnO_(2) cathode hardly appears,and the obtained discharge capacity may mainly come from the intercalation of Zn^(2+).Moreover,the utilization of ultra⁃high concentration electrolyte could not only improve the reversibility of Ti_(3)C_(2)T_(x)/MnO_(2) electrodematerial but also effectively inhibit the dissolution of electrode material in the cycling process(78.2%capacity retention afte

关 键 词：水系锌电池 Ti_(3)C_(2)T_(x)/MnO_(2) 电化学性能 三氟甲基磺酸四乙基铵 三氟甲烷磺酸锌 

分 类 号：O614.411[理学—无机化学] O614.711[理学—化学]