【作者】 徐艳； 刘霞； 刘云霞； 周小四；

【Author】 Yan Xu;Xia Liu;Yunxia Liu;Xiaosi Zhou;School of Chemistry and Materials Science,Nanjing Normal University;

【机构】 南京师范大学；

【摘要】 锗作为锂离子电池负极材料由于其高理论容量(1600 mA h g-1)、高扩散系数(100 cm2 s-1)和高电导率(2.17 s m-1)而受到广泛关注,但在脱-嵌过程中存在显著的体积变化而导致容量的快速衰退[1,2]。本文采用简单的溶液法制备出锗纳米颗粒/石墨烯纳米复合物,它在作为锂离子电池负极时表现出长循环寿命(电流密度为500 mA g-1循环1000圈后容量约为730 mA h g-1)和高倍率性能(电流密度为10 A g-1时容量为550 mA h g-1)。分析表明,所制备纳米复合物中石墨烯和锗纳米颗粒分别促进了电子传输与锂离子扩散;另外,石墨烯的包覆减少了锗与电解液的接触面积,从而抑制了固体电解质膜的持续生长。更多还原

【Abstract】 Germanium(Ge) has attracted extensive attention as anode materials for lithium-ion batteries(LIBs) because of its high theoretical capacity(1600 mA h g-1),high diffusivity,and high conductivity.However,Ge undergoes large volume change during lithiation/delithiation process,resulting in a rapid capacity fading.In this work,we synthesized Ge nanoparticles/reduced graphene oxide nanocomposites via a facile solution method.When used as anode materials for LIBs,the as-synthesized nanocomposites manifest long cycle life(730 mA h g-1 after 1000 cycles under 500 mA g-1) and excellent rate performance(550 mA h g-1 under 10 A g-1).The superior electrochemical performance can be attributed to following aspects.First,the graphene sheets and nanometer-sized Ge particles could promote the electron and lithium ion transport,respectively.Second,the graphene coating decreases the contact area between Ge nanoparticles and electrolyte,thereby suppressing the continuous growth of solid electrolyte interphase film.更多还原