沥青多孔炭@C_(3)N_(4)复合载硫体制备及锂硫电池电化学性能  

Pitch Porous Carbon@C_(3)N_(4) Composite Sulfur Carrier and Electrochemical Properties of Lithium-Sulfur Batteries

作　　者：董伟[1,2] 李粟 赵美娜 孟令强 杨芳 洪晓东[3] 吴晓光 纪凌枭 沈丁[1,2] 杨绍斌 DONG Wei;LI Su;ZHAO Meina;MENG Lingqiang;YANG Fang;HONG Xiaodong;WU Xiaoguang;JI Lingxiao;SHEN Ding;YANG Shaobin(College of Material Science and Engineering,Liaoning Technical University,Fuxin 123000,Liaoning,China;Key Laboratoryof Mineral High Value Conversion and Energy Storage Materials of Liaoning Province,Liaoning Technical University,Fuxin 123000,Liaoning,China;School of Materials Science and Hydrogen Energy,Foshan University,Foshan 528000,Guangdong)

机构地区：[1]辽宁工程技术大学材料科学与工程学院,辽宁阜新123000 [2]辽宁省矿物高值化与储能材料重点实验室,辽宁阜新123000 [3]佛山科学技术学院材料科学与氢能学院,广东佛山528000

出　　处：《硅酸盐学报》2024年第1期30-45,共16页Journal of The Chinese Ceramic Society

基　　金：国家自然基金(21808095);辽宁省教育厅基本科研项目(LJKZ0339,LJKMZ20220669);辽宁省应用基础研究计划项目(2023JH2/101300213)。

摘　　要：锂硫电池具有比容量高、能量密度大、环境友好等优点,是一种有前途的储能体系,但穿梭效应和导电性差等问题严重限制锂硫电池的发展。通过模板法制备了沥青多孔碳材料,通过与尿素混合后高温分解,成功制备了沥青多孔炭与C_(3)N_(4)的复合载硫材料(AC/C_(3)N_(4))。沥青多孔碳比表面积大、孔隙率高且导电性良好,有利于对多硫化物的捕获和电解质的渗透,加速了Li+和电子的传输。极性C_(3)N_(4)粘附在多孔碳表面和孔隙,有效提高材料对可溶性多硫化锂(Li_(2)S_(x),4≤x≤8)的吸附和催化,减少穿梭效应,保证了长循环的稳定性。载硫后获得的正极材料(AC/C_(3)N_(4)/S)在1 C电流密度下的首次放电容量为857 mA·h/g,循环400圈后容量仍剩余507 mA·h/g。在2 C电流密度下循环500圈后容量仍剩余495 mA·h/g,每圈容量衰减率为0.04%,具有良好的大电流循环性能。AC/C_(3)N_(4)/S在0.2、0.5、1.0、2.0、4.0 C和0.2 C电流密度下平均放电比容量为986、815、736、640、520 mA·h/g和859 mA·h/g,倍率性能良好。Introduction Lithium-sulfur batteries are one of the most promising secondary rechargeable batteries due to their high energy density,environmental friendliness,abundant reserves and low price.However,lithium-sulfur batteries have some problems such as poor electrical conductivity at the cathode,structural damage caused by volume expansion during charging and discharging,and shuttle effect caused by polysulfide dissolution,seriously restricting the development of lithium-sulfur batteries.One of the effective methods to solve the problems above is to prepare sulfur-carbon composite cathode materials by using carbon materials as sulfur carriers.Among them,porous carbon can increase the loading of monolithic sulfur,improve the electrical conductivity of the cathode material,inhibit the dissolution of soluble lithium polysulfide,and alleviate the volume expansion.It cannot inhibit the dissolution of soluble lithium polysulfide effectively for a long time due to the weak interaction between the no npolar and polar soluble lithium polysulfide of the carbon material.Pyridine nitrogen has the maximum binding energy with soluble lithium polysulfide(Li_(2)S_(x),4≤x≤8),which has the most obvious inhibition effect on the shuttle effect.The nitrogen in C_(3)N_(4)is as high as 55.1%,and it is mainly pyridine nitrogen.The preparation method is simple and low cost.Therefore,C_(3)N_(4)modified bituminous mesoporous carbon composites were proposed as sulfur carriers for lithium-sulfur composite batteries.The morphology and structure of the composites,the effect of the composites on the adsorption-catalyzed conversion of soluble lithium polysulfide(Li_(2)S_(x),4≤x≤8),and the electrochemical performance of lithium-sulfur batteries were investigated.Methods 5%mass fraction silane coupling agent(KH550)aqueous solution was used to surface treat SiO_(2)nanopowder(Jinan Zhiding Welding Materials Co.,Ltd.,China)and then porous carbon materials were prepared with treated SiO_(2)powder with asphalt powder.The porous carbon material

关 键 词：锂硫电池 氮化碳 多孔炭 复合材料 

分 类 号：TB332[一般工业技术—材料科学与工程]