摘要
可充镁电池(RMBs)是下一代最具潜力的储能体系之一,电解液对RMBs的性能具有重要影响.本文通过将1-乙基-3-甲基咪唑鎓四氟硼酸盐(EMImBF_(4))添加到MgCl_(2)+AlCl_(3)电解液(MACC)中,构建了一种MACC-EMImBF_(4)/有机醚(MACCE)可充镁电池电解液体系;采用循环伏安(CV)、线性扫描伏安(LSV)、电化学交流阻抗谱(EIS)和恒流充放电曲线(GCD)等方法测试了MACCE电解液的电化学性能及全电池性能;并通过场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对循环后的电极表面进行了分析.结果表明,EMImBF_(4)的添加有效改善了电解液的性能,MgCl_(2)-AlCl_(3)与EMImBF_(4)的最佳摩尔比为5∶1.MACCE电解液的离子电导率为3.94 mS/cm,Mg^(2+)沉积-溶出过电位为59 mV,库仑效率达97.5%以上,氧化稳定电位可达2.8 V(vs.Mg/Mg^(2+))且循环时间超过500 h.MACCE电解液在循环过程中可在Mg负极表面形成一层纳米颗粒层,有助于改善循环稳定性.MACCE电解液与正极材料Mo6S8的兼容性好,Mo6S8|MACCE|Mg全电池的放电平均比容量可达64.4mA∙h/g(12.88mA/g,0.1C),100次循环后比容量保持率可达73.2%.
Rechargeable magnesium batteries(RMBs)are considered to be one of the next most promising energy storage systems.The electrolyte has an important influence on the performance of RMBs.The RMBs electrolyte system of MACC-EMImBF_(4)/organic ether(MACCE)was prepared by the addition of 1-ethyl-3-methyl-1H-imidazol-3-ium tetrafluoroborate(EMImBF_(4))into the magnesium aluminum chloride complex(MACC)electrolyte.The electro-chemical performance and full cell performance of the MACCE electrolyte were tested by cyclic voltammetry(CV),linear scanning voltammetry(LSV),electrochemical impedance spectroscopy(EIS),and galvanostatic charge-discharge curves(GCD).The surface of the electrodes with MACCE electrolyte after circulation was analyzed by field emission scanning electron microscopy(FESEM),X-ray powder diffractometry(XRD)and X-ray photoelectron spectroscopy(XPS).The results show that the addition of EMImBF_(4) can effectively improve the electrolyte performance,and the optimum molar ratios of MgCl_(2)-AlCl_(3) to EMImBF_(4) is 5∶1.MACCE electrolyte has superior electrochemical performances with a high ionic conductivity(ca.3.94 mS/cm),a low overpotential(ca.59 mV),a high Coulombic efficiency(more than 97.5%),a high anodic stability[ca.2.8 V(vs.Mg/Mg^(2+))],and a long-term(more than 500 h)cycling stability.The analysis results demonstrate that a nanoparticles layer can be formed on the surface of Mg anode during cycling,which is helpful to improve the cycling stability.Moreover,MACCE displays good compatibility with the Mo6S8 cathode material.The Mo6S8|MACCE|Mg full cell delivers a discharge specific capacity of 64.4 mA∙h/g(12.88 mA/g,0.1C),which can retain ca.73.2%even after 100 cycles.MACCE electrolyte is simple to be prepared,low cost,and can be applied to RMBs,which is of great significance to accelerate the commercial application of RMBs.
作者
文家新
叶俊镠
魏鑫
杨京东
尹雪娇
李凌杰
WEN Jiaxin;YE Junliu;WEI Xin;YANG Jingdong;YIN Xuejiao;LI Lingjie(School of Architectural and Engineering,Chongqing Industry Polytechnic College,Chongqing 401120,China;College of Materials Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;School of Chemistry and Chemical Engineering,Chongqing University,Chongqing 400044,China)
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第5期120-128,共9页
Chemical Journal of Chinese Universities
基金
重庆市教委科学技术研究项目(批准号:KJQN202103202,KJQN202103210,KJZD-K202203203)
重庆工业职业技术学院博士研究基金(批准号:2022GZYBSZK2-11)资助.
