摘要
以EDTA二钠和PVP分别为络合剂和分散剂,应用碱性硼氢化钠溶液还原氯化钴溶液制备了非晶态Co-B合金。合金样品的形貌、组成、比表面积、结构和电化学性能分别由SEM、EDS、BET、X-射线衍射和循环伏安、恒电流充放电方法进行表征。结果表明,EDTA二钠能明显提高合金产品中B含量,而PVP则能有效阻止还原过程中Co-B合金颗粒团聚,增大其比表面积。在600 mA/g高电流密度下,分别添加PVP、EDTA二钠和EDTA二钠+PVP制备的三种合金电极容量依次为216.8mAh/g、260.9 mAh/g和288 mAh/g,甚至在高达1200 mA/g电流密度下,添加EDTA二钠+PVP制备出的Co-B合金电极仍然保持有234.1mAh/g的可逆放电容量。高B含量和大比表面积有利于提高Co-B合金的电化学容量和高倍率性能。
Amorphous Co-B alloys were prepared by a chemical reduction method using alkaline NaBH4 solution, EDTA and polyvinylpyrrolidone （PVP） as reduction reagent, the complex agent and dispersant, respectively, to reduce the COC12 solution. Morphology, composition, specific surface area, structure and electrochemical performances of the alloys were characterized by SEM, EDS, BET, XRD, cyclic vohammetry （CV） and charge-discharge test. Results showed that B content of the alloys can be improved by EDTA and PVP can effectively avoid the aggregation of alloy particles. At a high rate of 600mA/g, capacity of the alloy prepared with PVP was only 216.8mAh/g, while capacity of the alloy prepared with EDTA and with EDTA＋PVP were 260.9 mAh/g and 288 mAh/g, respectively. Even at a rate of 1200 mA/g, the alloy prepared with EDTA＋PVP still can deliver a reversible capacity of 234.1mAh/g, which was attributed to its high B content and large specific surface area.
出处
《广州化工》
CAS
2009年第2期66-69,共4页
GuangZhou Chemical Industry
基金
广东省高等学校建设专项资金项目(育苗工程)
关键词
非晶态Co-B合金
高倍率性能
二次碱性电池
负极材料
Amorphous Co-B alloy
high-rate dischargeability
secondary alkaline battery
anode material
