摘要
以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为结构导向剂,正硅酸乙酯(TEOS)为硅源,柠檬酸为碳源,采用水热法得到凝胶状二氧化硅/碳前驱体,采用旋转蒸发方式去除溶剂,通过高温热处理,得到棒状硅氧基碳负极活性材料,提高浆料体系无紧密束缚环境下硅碳材料的性能。借助X射线衍射(XRD)仪、无机元素分析(EA)仪、比表面积及孔隙度分析仪和扫描电子显微镜(SEM)对棒状硅基材料进行结构和形貌表征。结果表明,合成的棒状硅基材料首尾相连,形成莲藕链束,长度约为1~3μm,直径约为200 nm,孔径为6.9 nm,比表面积为282 m^(2)/g。与管长>5μm,比表面积900 m^(2)/g,直径1~2 nm的单壁碳纳米管导电剂在电解液体系中形成长程、短程互补的多级网络,加上大量介孔的存在,有利于保持浆料悬浮稳定性。用世伟洛克电池进行电化学性能测试,电化学测试结果表明首次放电比容量为1300 mAh/g,充电比容量为726 mAh/g,首效为55.8%,在0.05 C下,循环50次充电比容量从726 mAh/g变为557 mAh/g,比容量保持率为76.7%。本工作在用P123为结构导向剂制备二氧化硅的过程中,引入碳源,得到同时具有碳包覆和碳还原二氧化硅的硅基材料,避免使用镁热还原二氧化硅,再碳包覆带来的复杂工艺流程。
In this study,a gel-like silica/carbon precursor was obtained by the hydrothermal method,with PEO-PPO-PEO(P123)as the structure directing agent,tetraethyl orthosilicate(TEOS)as the silicon source,and citric acid as the carbon source.The solvent was removed by rotary evaporation.The rod-like carbon-coated silicon oxide-negative material was obtained through high-temperature heat treatment,which improved the performance of the silicon-carbon material in the slurry system without a tight binding environment.The structure and morphology of this material were characterized by X-ray diffraction,inorganic element analyzer,specific surface area and porosity analyzer,and scanning electron microscope.The rod-like silicon-based material was joined end to end to form a lotus chain bundle having a length of about 1~3μm,diameter of about 200 nm,pore size of 6.9 nm,and specific surface area of 282 m^(2)/g This material and a single-walled carbon nanotube conductive agent with tube length>5μm,specific surface area of 900 m^(2)/g,and diameter of 1~2 nm form a multistage network of long and short range complementary in the electrolyte system.In addition,the presence of a large number of mesoporous materials was conducive to maintaining the suspension stability of slurry.The electrochemical performance test of the Swagelok battery showed that the initial discharge capacity was 1300 mAh/g,charging capacity was 726 mAh/g,and the coulombic efficiency was 55.8%.At 0.05 C,the charging capacity changed from 726 mAh/g to 557 mAh/g after 50 cycles,and the specific capacity retention rate was 76.7%.This work directly introduced carbon sources in the process of preparing silica with P123 as the structure guide agent and obtained silica-based materials with both carbon coating and carbon-reducing silica at the same time.Thus,this process avoided the complex technological process caused by magnesium thermal reduction of silica and recarbon coating.
作者
阮晶晶
刘福园
李珅珅
高桂红
刘艳侠
RUAN Jingjing;LIU Fuyuan;LI Shenshen;GAO Guihong;LIU Yanxia(Zhengzhou Institute of Emerging Industrial Technology,Henan Key Laboratory of Energy Storage Materials and Processes,Zhengzhou 450003,Henan,China;Beijing Key Laboratory of Ionic Liquids Clean Process,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2023年第4期1051-1058,共8页
Energy Storage Science and Technology
基金
国家重点研发计划项目(2019YFA0705603)
河南省重点研发计划项目(221111240100)。
关键词
锂浆料电池
负极材料
棒状硅基材料
碳源
lithium slurry battery
anode material
rod-like silicon-based material
carbon source
