金属间化合物CoSb_2电化学吸放锂特性的研究

Study on Electrochemical Lithium Absorption/Release Properties of Intermetallic Compound CoSb_2

采用悬浮熔炼和球磨方法制备了CoSb2合金粉末,并研究了它的电化学吸放锂性能。研究结果表明,具有marcasite结构的CoSb2 的首次可逆容量为263 mAh穏-1, 相应的体积比容量为2 130 mAh穋m-3。经过 15 个循环后,其可逆容量衰减到 123 mAh穏-1。在本实验中发现,把中间相微碳球(MCMB)加入到CoSb2 中不仅能改善其循环寿命,而且也能够明显提高其可逆容量。非原位XRD 测试的结果表明,虽然 marcasite 结构的CoSb2 本身并不能存储锂,但其结构破坏后形成的锑能与锂进行可逆的电化学反应。

Intermetallic compound CoSb2 powders were prepared by levitation melting and ball-milling. The electrochemical lithium absorption/release properties of CoSb2 were investigated. The experimental results show that the first reversible capacity of marcasite CoSb2 is 263 mAh(.)g(-1), corresponding to the volumetric capacity of about 2 130 mAh(.)cm(-3). The reversible capacity will be decreased to 123 mAh(.)g(-1), after 15 cycles. In our present work, it is found that addition of meso-carbon micro beads (MCMB) into CoSb2 not only increases its reversible capacity, but also improves its cycle life notably. Ex-situ XRD tests show that although marcasite CoSb2 itself can not intercalate lithium; the Sb formed by the decomposition of CoSb2 can react reversibly with Li.