摘要
近年来,人们对利用低温炭化工艺制备煤基无定形炭材料作为锂离子电池(LIBs)和钠离子电池(SIBs)的负极材料产生了兴趣。然而,煤衍生炭材料的炭化机制仍然不太清楚。因此,本文选取烟煤为原料,探究了煤炭到无定形炭材料的化学、微晶和孔隙结构演变过程。随着温度的升高(低于1000℃),材料结构发生局部变化,碳层的迁移和小分子物质的释放导致了层间距(3.69-3.82A)和缺陷密度(1.26-1.90)逐渐增大,并且产生了丰富的纳米微孔结构。当温度升至1000~1600℃时,层间距和缺陷密度开始逐渐减小。在LIBs中,经1000℃炭化制备的样品表现出最佳的电化学性能。在0.1 C倍率测试下可逆容量达到384 mAh g^(-1),在5 C倍率下仍能保持170 mAh g^(-1),表现出优异的倍率性能。在SIBs中,经1200℃炭化制备的样品在0.1 C倍率测试下具有270.1 mAh g^(-1)的可逆容量和高达86.8%的首次库伦效率。本研究为煤基炭材料的精细化制备提供了理论支撑。
Despite recent interest in the low-temperature carbonization of coal to prepare disordered carbon materials for the anodes of lithium-ion(LIBs)and sodium-ion batteries(SIBs),the carbonization mechanism is still poorly understood.We selected bituminous coal as the raw material and investigated the chemical,microcrystal,and pore structure changes during the carbonization process from coal to the resulting disordered carbon.These structural changes with temperature below 1000℃ show an increase in both interlayer spacing(3.69-3.82A)and defect concentration(1.26-1.90),accompanied by the generation of a large amount of nano-microporous materials.These changes are attributed to the migration of the local carbon layer and the release of small molecules.Furthermore,a decrease in interlayer spacing and defect concentration occurs between 1000℃ and 1600℃.In LIBs,samples carbonized at 1000℃ showed the best electrochemical performance,with a reversible capacity of 384 mAh g^(-1) at 0.1 C and excellent rate performance,maintaining 170 mAh g^(-1) at 5 C.In SIBs,samples carbonized at 1200℃ had a reversible capacity of 270.1 mAh g^(-1) at 0.1 C and a high initial Coulombic efficiency of 86.8%.This study offers theoretical support for refining the preparation of carbon materials derived from coal.
作者
田青青
李晓明
谢莉婧
苏方远
易宗琳
董良
陈成猛
TIAN Qing-qing;LI Xiao-ming;XIE Li-jing;SU Fang-yuan;YI Zong-lin;DONG Liang;CHEN Cheng-meng(Key Laboratory of Coal Processing and Efficient Utilization,China University of Mining and Technology,Xuzhou 221116,China;CAS Key Laboratory of Carbon Materials,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;School of Chemical Engineering&Technology,China University of Mining&Technology,Xuzhou 221116,China)
出处
《新型炭材料（中英文）》
SCIE
EI
CAS
CSCD
北大核心
2023年第5期939-953,共15页
New Carbon Materials
基金
陕西省自然科学基础研究计划(2019JLZ-10)
国家自然科学基金委员会面上基金项目(22179139)
山西省基础研究计划面上基金项目(20210302123008,20210302124101)
山西省重点研发计划项目(2022ZDYF028).
关键词
煤
炭化机制
炭材料
锂离子电池
钠离子电池
Coal
Carbonization mechanism
Carbon materials
Lithium-ion batteries
Sodium-ion batteries
