摘要
将微米Si和纳米Ag_(2)O进行机械球磨,通过原位固相反应合成了Si基复合材料[Si/(SiO+Ag)],以沥青为碳源采用高温煅烧法制备了碳包覆Si基复合材料[Si/(SiO+Ag)-C]。采用XRD、XPS、SEM、TEM对复合材料进行了表征,测试了其电化学性能。结果表明,微米Si和纳米Ag_(2)O在球磨破碎过程中原位形成Si O和Ag颗粒,并附着在基体Si上,两种复合材料都展现出良好的倍率性能,在低电流密度(0.12 A/g)下Si/(SiO+Ag)和Si/(SiO+Ag)-C循环5次后分别表现出1422和1039 mA·h/g的可逆比容量,而在高电流密度(2.40 A/g)下仍能获得672和393 mA·h/g的可逆比容量;当电流密度再次恢复到0.12 A/g时,可逆比容量可恢复到1329和961m A·h/g,Si/(SiO+Ag)-C表现出更好的循环稳定性,经80次循环后可逆比容量仍稳定在943 m A·h/g,其突出的倍率性能归因于微米Si的颗粒细化以及球磨过程中原位反应形成纳米Ag颗粒导电特性,而循环稳定性的提高与原位形成Si O和包覆碳构成的双相缓冲结构有关。
Silicon-based composite[Si/(Si O+Ag)]was synthesized by in situ solid phase reaction of micron-Si and nano Ag_(2O) treated with mechanical ball milling.Carbon-coated si-based composite[Si/(SiO+Ag)-C]was then obtained by high-temperature calcination of[Si/(SiO+Ag)]using asphalt as carbon source.The composites were characterized by XRD,XPS,SEM and TEM,followed by evaluation on their electrochemical properties.The results showed that SiO and Ag particles were formed by micron-Si and nano Ag_(2O) in situ during the ball milling process,and adhered to the matrix Si.Both of the two composites exhibited excellent rate performance,with reversible specific capacities of 1422 and1039 mA·h/g at low current density (0.12 A/g) after 5 cycles,and of 672 and 393 mA·h/g at high current density (2.40 A/g),respectively.When the current density was restored to 0.12 A/g again,the reversible specific capacities were restored to 1329 and 961 mA·h/g.Si/(SiO+Ag)-C exhibited better cycle stability,with the reversible specific capacity still maintained above 943 m A·h/g after 80 cycles.This outstanding rate performance was attributed to the refinement of micron-Si particles and the electrical conductivity of nano-Ag particles formed in-situ,while the improvement in cycle stability was related to the dual-phase buffer structure of SiO and coated carbon formed in-situ.
作者
王帅
唐梦
蔡振飞
曹瑞
马扬洲
宋广生
WANG Shuai;TANG Meng;CAI Zhenfei;CAO Rui;MA Yangzhou;SONG Guangsheng(School of Materials Science and Engineering,Anhui University of Technology,Maanshan 243000,Anhui,China)
出处
《精细化工》
EI
CAS
CSCD
北大核心
2024年第1期107-113,共7页
Fine Chemicals
基金
国家自然科学基金项目(52207246)
国家级外国专家引进计划项目(G20190219004)
安徽省教育委员会自然科学研究项目(KJ2020A0263,YJS20210336)
先进金属材料绿色制造与表面技术重点实验室资助项目(GFST2022ZR02,GFST2021KF01)。
关键词
锂离子电池
复合材料
Si负极材料
固相反应
机械化学
功能材料
lithium-ion batteries
composites
Si anodes
solid state reaction
mechanochemistry
functional materials
