摘要
The coupling between electrochemically active material and conductive matrix is vitally important for high efficiency lithium ion batteries （LIBs）. By introducing oxygen groups into the nanoporous carbon framework, we accom- plish sustainably enhanced electrochemical performance for a SnO2/carbon LIB. 2-5 nm SnO2 nanoparticles are hydro- thermally grown in different nanoporous carbon frameworks, which are pristine, nitrogen- or oxygen-doped carbons. Compared with pristine and nitrogen-doped carbon hosts, the SnO2/oxygen-doped activated carbon （OAC） composite ex- hibits a higher discharge capacity of 1,122mAhg^-1 at 500 mA g^-1 after 320 cycles operation and a larger lithium storage capacity up to 680 mAhg-I at a high rate of 2,000 mA g^-1. The exceptional electrochemical performance originated from the oxygen groups, which could act as Lewis acid sites to attract electrons effectively from Sn during the charge process, thus accelerating reversible conversion of Sn to SnO2. Meanwhile, SnO2 nanoparticles are effectively bonded with carbon through such oxygen groups, thus preventing the electrochemical sintering and maintaining the cycling stability of the SnO2/OAC composite anode. The high electrochemical performance, low biomass cost, and facile preparation renders the SnO2/OAC composites a promising candidate for anode materials.
通过电化学活性材料与导电载体材料复合制备纳米复合材料,对于高能量锂离子电池的发展至关重要.本文利用水热法将含氧官能团引入到纳米孔碳材料骨架上,制备得到了骨架内均匀生长粒径为2–5 nm的SnO_2纳米颗粒的纳米孔碳材料,作为SnO_2/碳复合负极材料其电化学性能显著提高.与原始(CAC)、氮掺杂碳(NAC)载体相比,氧掺杂碳载体(OAC)制备得到的SnO_2/碳复合材料表现出更优异的电化学性能.SnO_2/OAC在500 mAg^(-1)充放电速率下,320圈后其放电容量保持在1122 mAhg^(-1);2000 mAg^(-1)下其容量仍保持680 mAhg^(-1).SnO_2/OAC优异的电化学性能主要归因于:氧官能团作为Lewis酸,可以在充电状态下从Sn纳米颗粒处吸引电子,促进Sn向SnO_2的可逆转化;同时,由于氧官能团的存在,SnO_2纳米颗粒被有效地限制在了碳载体骨架内,有效抑制了充放电过程中SnO_2纳米颗粒的团聚,从而提高了SnO_2/OAC复合负极材料的电化学稳定性.综上,优异的电化学性能、低的生物质成本以及简易的制备方法使得SnO_2/OAC复合材料成为一种非常有潜力的锂电池负极材料.
作者
Zhen Geng
Bing Li
Hezhi Liu
Hong Lv
Qiangfeng Xiao
Yongjun Ji
Cunman Zhang
耿振;李冰;刘合之;吕洪;肖强凤;纪永军;张存满(Clean Energy Automotive Engineering Center,Tongji University,Shanghai 201804,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;General Motors Research and Development Center,Warren,MI 48090,USA)
基金
supported by the National High Technology Research and Development Program of China(2012AA053305 and 2014AA052501)
the National Natural Science Foundation of China(21506224)
