Na_(3)V_(2)(PO_(4))_(3)@C用作水系锌离子电池正极材料的研究  

Na_(3)V_(2)(PO_(4))_(3)@C cathode material for aqueous zinc-ion batteries

作　　者：衡永丽 谷振一 郭晋芝[2] 吴兴隆[1,2] HENG Yongli;GU Zhenyi;GUO Jinzhi;WU Xinglong(Faculty of Chemistry,Northeast Normal University;MOE Key Laboratory for UV Light-Emitting Materials and Technology,Northeast Normal University,Changchun 130024,Jilin,China)

机构地区：[1]东北师范大学化学学院 [2]东北师范大学,紫外光发射材料与技术教育部重点实验室,吉林长春130024

出　　处：《储能科学与技术》2021年第3期938-944,共7页Energy Storage Science and Technology

基　　金：国家自然科学基金重大研究计划项目(91963118)。

摘　　要：水系锌离子电池(AZIBs)是未来大型储能领域中具有吸引力的选择之一。但合适的用于锌离子存储的正极材料少之又少。本工作以NASICON结构的正极材料Na_(3)V_(2)(PO_(4))_(3)(NVP)作为储锌正极材料,在高浓度的电解液中可以实现高效的Zn^(2+)存储并展现出超长的循环性能。本研究采用简单的溶胶凝胶法制备出均匀碳包覆的NVP,并借助X射线衍射(XRD)、扫描电子显微镜(SEM)、恒流充放电等表征测试手段,分析NVP材料的结构、形貌和用作AZIBs正极时表现出的电化学性能。同时,本工作研究了不同浓度的电解液对电化学性能的影响。结果表明,电解液浓度提升后NVP材料可以展现出更高的容量存储、卓越的倍率性能和超长的循环寿命。在2000 mA/g的超高电流密度下循环1000圈之后,容量保持率仍为77.8%,并且在循环过程中材料的每圈库仑效率接近100%。此外,通过循环伏安法(CV)和恒电流间歇滴定法(GITT)进一步探索了NVP电极的动力学过程并得出,NVP材料出色的电化学性能的表现归因于其稳定和开放的NASICON框架和优异的动力学行为。Aqueous zinc-ion batteries(AZIBs)are an attractive choice for large-scale energy storage in the future.However,suitable cathode materials for Zn^(2+)storage are lacking.This work finds that the cathode material Na_(3)V_(2)(PO_(4))_(3)(NVP)with the natrium super ionic conductor(NASICON)structure can achieve efficient Zn2+storage and ultralong-cycle performance in high-concentration electrolytes.In this paper,a simple sol-gel method is used to prepare a uniform carbon-coated NVP.With the help of X-ray diffraction,scanning electron microscopy,constant current charge-discharge,and other characterization test methods,the structure,morphology,and performance of the NVP materials when used as cathode for AZIBs are analyzed.Additionally,the effects of different concentrations of electrolytes on the electrochemical performances are studied.The results show that NVP materials can provide high-capacity storage,excellent rate performance,and long-cycle life as the electrolyte concentration increases.After 1000 cycles at a high current density of 2000 mA·g^(−1),the capacity retention rate is still 77.8%,and the coulombic efficiency per cycle of the material is close to 100%.Furthermore,the kinetic process of the NVP electrode is explored through cyclic voltammetry and galvanostatic intermittent titration technique.Experiments prove that these excellent electrochemical performances can be attributed to the stable and open NASICON framework and excellent kinetic behavior.

关 键 词：水系锌离子电池 正极材料 磷酸钒钠 高浓度电解液 长循环寿命 

分 类 号：O646.21[理学—物理化学]