氟氮共掺杂多孔碳纳米片的制备及其储钾性能研究  

Research on the Preparation and Potassium Storage Performance of F,N Co-doped Porous Carbon Nanosheets

作　　者：蒋江民 郑欣冉[1] 孟雅婷 贺文杰 陈亚鑫 庄全超 袁加仁[3] 鞠治成 张校刚[2] Jiang Jiangmin;Zheng Xinran;Meng Yating;He Wenjie;Chen Yaxin;Zhuang Quanchao;Yuan Jiaren;Ju Zhicheng;Zhang Xiaogang(School of Materials Science and Physics,China University of Mining and Technology,Xuzhou 221116,China;School of Material Science and Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China;School of Physics and Materials,Nanchang University,Nanchang 330038,China;School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]中国矿业大学材料与物理学院,徐州221116 [2]南京航空航天大学材料科学与技术学院,南京211106 [3]南昌大学物理与材料学院,南昌330038 [4]河南理工大学材料科学与工程学院,焦作454003

出　　处：《化学学报》2023年第4期319-327,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(22209204,22279162,21975283);江苏省自然科学基金(BK20221140);中国博士后科学基金(2022M713364)资助。

摘　　要：钾离子电容器是一种新型的电化学储能器件,碳基材料被认为是最有前途的储钾候选材料之一.然而,K+半径较大使得迁移速率缓慢,脱嵌过程中材料的结构易破坏,导致性能显著下降.因此,开发出低成本的碳材料来适应K+扩散的热力学与动力学需求,已成为当前发展的瓶颈.煤沥青是煤焦油经蒸馏提取液体馏分后得到的残余物,它的组成主要为稠环芳烃,具有高的含碳量、可塑性好、资源集中、价格低廉等显著优点,是一种优质的碳基材料前驱体.鉴于此,本工作采用煤沥青作为碳源、聚四氟乙烯为氟源,氯化钠为模板剂,通过直接高温碳化的策略制备了氟氮共掺杂的多孔碳纳米片(FNCPC).研究表明,纳米片层的结构设计有效缩短了离子的传输路径,F、N共掺杂拓宽了碳的层间距,缓解了体积膨胀问题,并且形成更多的表面缺陷,可为K+的存储提供更多的反应活性位点.此外,电化学动力学分析和密度泛函理论(DFT)表明,FNCPC具备显著的赝电容特性和强的对K吸附能.得益于结构和化学性质的协同优化,FNCPC负极展现出优异的储钾能力(2 A·g^(-1)电流密度下具有212.8 mAh·g^(-1)的比容量)和循环稳定性.进一步将商业化活性炭(AC)为正极,FNCPC为负极构筑了钾离子电容器(AC//FNCPC),该器件能实现最大的能量密度为87.5 Wh·kg^(-1),并且在循环3000次后具有86.1%的容量保持率,展现出广阔的应用前景.Potassium-ion capacitor(PIC)is a new type of electrochemical energy storage device,and carbon-based materials are considered as one of the most promising candidate anode materials for K+storage.However,the migration rate of K+is slow and the material structure is easy to be damaged during the intercalation and de-intercalation processes because the K+has a larger radius,resulting in a significant decline in performance.Therefore,the development of low-cost carbon materials to meet the thermodynamic and kinetic requirements of K+diffusion has become the bottleneck of current development.In this work,the F and N co-doped porous carbon nanosheets(FNCPC)were prepared by direct high-temperature carbonization,in which the low-cost coal pitch as the carbon source,polytetrafluoroethylene as the fluorine source and sodium chloride as the template agent.The structure design of the nanosheet effectively shortens the transport path of ions,and the co-doping of F and N widens the layer spacing of carbon,alleviates the volume expansion problem,and also forms more surface defects,which provides more reactive sites for K+storage.In addition,electrochemical kinetic analysis and density functional theory(DFT)show that the FNCPC has remarkable pseudocapacitance characteristics and strong K adsorption energy.Benefiting from the synergistic optimization of structure and chemical properties,the FNCPC anode exhibits excellent potassium storage capacity(a high specific capacity of 212.8 mAh·g^(-1) at 2 A·g^(-1))and good cyclic stability.Furthermore,the PIC(AC//FNCPC)was constructed by using commercial activated carbon(AC)as cathode electrode and FNCPC as anode electrode,which delivers a maximum energy density of 87.5 Wh·kg^(-1),and has a capacity retention rate of 86.1% after 3000 cycles,showing a very broad application prospect.

关 键 词：钾离子电容器 碳纳米片 煤沥青 氟氮共掺杂 吸附能 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TM53[电气工程—电器]