【摘要】 以蔗糖为原料,采用水热法制备了硬碳(HC)负极材料。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、恒电流充放电测试等方法研究了溶液浓度和热处理温度对材料相结构、颗粒形貌及电化学性能的影响。结果表明,随溶液浓度的提高,硬碳粉体颗粒度逐渐加大。但过低浓度制备的纳米硬碳颗粒易团聚,过高浓度易引起颗粒的异常长大。热处理温度过低材料表面会残存有机物,而温度太高易导致颗粒长大,这些都不利于材料电化学性能的发挥。蔗糖溶液浓度为5%(质量分数)、热处理温度为700℃时制备的硬碳,颗粒细小且分布均匀,表现出较高的可逆比容量(~260mAh/g)、优异的倍率性能和循环稳定性。更多还原

【Abstract】 Hard carbon(HC) material was prepared via a hydrothermal route from sucrose. The effects of the concentration of sucrose solution and the heat-treatment temperature on the phase structure,the particle morphology and the electrochemical performance of the prepared HC material were investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM) and constant current charge-discharge tests. The results reveals that the particle size of HC powders increases with increasing concentration of sucrose solution. Too lower concentration easily leads to the aggregation of the obtained nano-particles while higher concentration results in the abnormal growth of HC particles. Lower heat-treatment temperature will result in some residual organic group on the particle surface of HC powders but higher temperature can cause the increase of the particle size. Both of which are unfavorable for the improvement of electrochemical performances. The sample synthesized from 5% sucrose solution and heat-treated at 700 ℃ exhibits a stable specific capacity of 260 mAh/g,excellent rate-capability and good cycling stability.更多还原