【作者】 张春倩； 李传波； 薛春来； 成步文； 王启明；

【Author】 Chunqian Zhang;Chuanbo Li;Chunlai Xue;Buwen Cheng;Qiming Wang;State Key Laboratory on Integrated Optoelectronics,Institute of Semiconductors,Chinese Academy of Sciences;

【机构】 中国科学院半导体研究所集成光电子重点实验室；

【摘要】 以多晶硅粉末作为原材料,通过金属催化腐蚀的方法制备了微纳结构硅负极材料(如图1)。相同条件下,与未处理过的多晶硅粉相比,其锂离子电池的循环寿命和阻抗性能都得到了改善。该纳米线微球结构材料中的外层纳米线可为电子及锂离子提供良好的传输通道,而核层的小尺寸硅粉又可以作为一个中枢来进行电子传导并维持电极的稳定性。图2给出了微纳结构硅粉作为负极材料的锂离子电池的电压容量图以及库伦效率,因表面电解质层的形成,第一周有21.7%的容量损失,但第二周库伦效率就达到97%以上,并迅速攀升至99%,到200周仍保持在99.5%以上。研究表明,粘结剂、电解液添加剂对电池寿命有较大影响,柔性SEI的形成及硬度适中的粘结剂均会缓解嵌锂膨胀造成的寿命衰减。循环阻抗测试表明,阻抗先增后减,SEI薄膜的形成及材料结构的熟化使电池维持良好的充放电特性。更多还原

【Abstract】 Hedgehog-like Si nanomaterial has been prepared by metal assisted chemical etching method with cheap polycrystalline Si powder as raw materials and used as anode for lithium-ion batteries.The cycle stability and impedance are greatly enhanced compared with pristine silicon powder,and the columbic efficiency(CE) holds above 99.5% up to 200+ cycles.The study of impedance performance also explained the stability of the anode material,for the split of the anode just takes place in the beginning of the discharging and charging process of the material.The improved electrochemical characteristics are attributed to its volume buffering and effective conductance due to the unique structure,which combines nanowires on the surface and a core inside.更多还原