摘要
碳包覆策略是能有效解决锂离子电池负极用过渡金属氧化物(TMO)材料在充放电过程中体积膨胀/收缩造成的粉化难题的一种有效途径.采用生物基可食用冰粉作为碳源与草酸高铁铵的水凝胶作为前驱物,经一步高温热解制备氮掺杂的冰粉基碳包覆Fe3O4,采用XRD、SEM、TEM、XPS、TGA、拉曼光谱、恒电流充放电测试、循环伏安和电化学阻抗谱等方法对样品的形貌、结构和电化学性能进行研究.结果表明,该方法可快速大量制备氮掺杂碳包覆Fe3O4多孔复合材料(N-C@Fe3O4),通过调整原料配比和热处理条件,获得优异的电化学性能.N-C@Fe3O4-5作为锂离子电池负极材料具有良好的循环稳定性(在0.1 A/g电流密度下循环下80圈保持762.74 mAh/g比容量)和较高的倍率性能.相关机理研究表明N-C@Fe3O4复合材料良好倍率性能主要来源于赝电容容量的贡献.复合材料优异的电化学性能是由于碳包覆能够防止纳米颗粒团聚,提高导电性以及形成稳定的固体电解质界面(SEI)膜.冰粉基碳包覆TMO是一种改善其电化学储锂性能的有效途径,可推广并改善其他锂离子电池氧化物负极的储锂性能.
Abstract
The carbon coating strategy is an effective way to solve the pulverization problem caused by the vol-ume expansion/shrinkage of transition metal oxide(TMO)materials for lithium-ion battery anodes during charge and discharge.In this paper,bio-based edible ice jelly powder was used as carbon source and ferric am-monium oxalate hydrogel was used as precursor,and nitrogen-doped ice jelly powder-based carbon-coated Fe3O4 was prepared by one-step high-temperature pyrolysis.The morphology,structure and electrochemical properties of the samples were studied by XRD,SEM,TEM,XPS,TGA,Raman spectroscopy,galvanostatic charge-dis-charge test,cyclic voltammetry and electrochemical impedance spectroscopy.The results show that this method can quickly and massively prepare nitrogen-doped carbon-coated Fe3O4 porous composites(N-C@Fe3O4),and excellent electrochemical performance can be obtained by adjusting the ratio of raw materials and heat treatment conditions.N-C@Fe3O4-5 as a lithium ion battery anode material has good cycle stability(762.74 mAh/g specif-ic capacity after 80 cycles at a current density of 0.1 A/g)and high rate capability.Relevant mechanism studies have shown that the good rate performance of N-C@Fe3O4 composites is mainly due to the contribution of pseudocapacitive capacity.The excellent electrochemical performance of the composite is attributed to the car-bon coating that prevents nanoparticle agglomeration,improves electrical conductivity,and forms a stable solid electrolyte interface(SEI)film.This work shows that ice jelly powder-based carbon-coated TMO is an effective way to improve the electrochemical lithium storage performance of TMO,which can be extended and improved the lithium storage performance of other lithium-ion battery oxide anodes.
基金项目
国家自然科学基金项目(51402030)
重庆市技术创新与应用发展专项重点项目(CSTB2022TIAD-KPX0031)
重庆科委基础科学与前沿技术研究重点项目(cstc2017jcyjBX0028)
重庆市研究生导师团队建设项目(JDDSTD2022006)
高端外国专家引进计划(G2022035007L)
重庆市自然科学基金面上项目(2022NSCQ-MSX1165)
重庆交通大学研究生科创项目(2023S0090)
万方数据