纳米TiO_(2)构筑于多通道炭纤维实现室温钠-硫电池中多硫化物的高效吸附  

Incorporating TiO_(2) nanoparticles into the multichannels of electro-spun carbon fibers to increase the adsorption of polysulfides in room temperature sodium-sulfur batteries

作　　者：叶鑫 李质奇 孙皓[1] 吴明霞 安仲勋 庞越鹏[1] 杨俊和[1] 郑时有[1] YE Xin;LI Zhi-qi;SUN Hao;WU Ming-xia;AN Zhong-xun;PANG Yue-peng;YANG Jun-he;ZHENG Shi-you(School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Aowei Technology Development Co.,Ltd,Shanghai 201203,China)

机构地区：[1]上海理工大学,材料学院,上海200093 [2]上海奥威科技开发有限公司,上海201203

出　　处：《新型炭材料（中英文）》2022年第6期1116-1124,共9页New Carbon Materials

基　　金：国家自然科学基金(51971146,51971147,52171218),上海市教委创新计划重大项目(2019-01-07-00-07-E00015),上海市科委项目(21010503100,20ZR1438400);启明星计划(20QA1407100);广西电子信息材料构效关系重点实验室(桂林电子科技大学)(201017-K)资助.

摘　　要：随着电动汽车和大规模储能电网的快速发展,锂离子电池将不可避免地面临有限的能量密度无法满足日益增长的需求和成本不断上升的两大困境。室温钠-硫电池因具有高能量密度和低成本的优势而备受关注,但其存在多硫化钠的“穿梭效应”导致电池的循环性能较差的问题,亟需解决。在此,本文提出将纳米TiO_(2)颗粒构筑于多通道炭纤维以稳定硫,从而实现室温钠-硫电池电化学性能的提高。首先通过静电纺丝和热处理技术制得有纳米TiO_(2)负载的多通道炭纤维载体材料,后续采用熔融扩散载硫方法制备出硫基复合正极材料。纳米TiO_(2)颗粒的加入可增强了对多硫化物的吸附力,同时促进其向Na2S2和Na2S的快速转化。在0.1 A g^(−1)电流密度条件下,电极材料经循环100次后的比容量为445.1 mAh g^(−1),库仑效率接近100%;即使在电流密度为2 A g^(−1)时,经500次循环,该电极材料仍保持有300.5 mAh g^(−1)的容量,显现出优异的倍率和循环性能。通过表征测试手段与理论计算相结合,验证了纳米TiO_(2)颗粒的加入可增强碳基材料对多硫化物的吸附作用。这项工作有望为高性能室温钠-硫电池正极材料的优化设计提供理论依据与技术指导。With the rapid development of electric vehicles and large-scale power grids,lithium-ion batteries inevitably face the problem that their limited energy density and high cost cannot meet the growing demand.Room temperature sodium-sulfur(RT Na-S)batteries,which have the potential to replace lithium-ion batteries,have become a focus of attention.However,the challenging problem of their poor cycling performance cause by the“shuttle effect”of the reaction intermediates(sodium polysulfides)needs to be addressed.We report a method to incorporate TiO_(2)nano particles into the multichannels of electrospun carbon fibers(TiO_(2)@MCCFs)to stabilize the sulfur compounds and produce high-performance RT Na-S batteries.The TiO_(2)@MCCFs were prepared by electrospinning followed by heat treatment,and were infiltrated by molten sulfur to fabricate S/TiO_(2)@MCCF cathode materials.The addition of the TiO_(2)nanoparticles increases the affinity of cathode materials for polysulfides and promotes the conversion of polysulfides to lower order products.This was verified by DFT calculations.A S/TiO_(2)@MCCF cathode with a S content of 54%has improved electrochemical rate and cycling performance,with a specific capacity of 445.1 mAh g^(−1)after 100 cycles at 0.1 A g^(−1)and a nearly 100%Coulombic efficiency.Even at 2 A g^(−1),the cathode still has a capacity of 300.5 mAh g^(−1)after 500 cycles.This work provides a new way to construct high performance RT Na-S battery cathodes.

关 键 词：钠-硫电池 正极 二氧化钛 静电纺丝 

分 类 号：TB33[一般工业技术—材料科学与工程]