不同形貌炭微球的制备及其电化学性能

Synthesis and electrochemical performance of carbon microspheres with different shapes

以2,4-二羟基苯甲酸与甲醛为反应物,F108为表面活性剂,L-赖氨酸为催化剂进行反应,再经碳化、水洗等过程制备了一系列炭微球。透射电子显微镜法(TEM)表明碳化后形成实心炭微球,通过控制水洗温度和水洗时间分别得到中心网格状炭微球和中空炭微球。恒电流充放电测试表明实心微球、中心网格状微球与反应时间分别为36、72 h时所合成的空心微球可逆比容量分别是450、865、559、和576 mAh/g,经过50次循环后可逆比容量分别为299、492、384和339mAh/g。首次和50次循环后可逆容量的大小按微球的形貌排列均是中心网格状炭微球>空心炭微球>实心炭微球,说明炭微球形貌对材料电化学性能有重要影响,且中心网格状微球性能最佳,比容量均超过石墨理论比容量372 mAh/g。

A series of carbon microspheres were prepared by using 2,4-dihydroxy benzoic acid and formaldehyde as reactant,F108 as surfant,L-lysine as catalyst through the processes of carbonization,rinsing and so on.TEM shows that solid carbon microsphere is formed after carbonization.The center grid and hollow carbon microspheres are obtained by controlling the rinsing temperature and time.Solid,grid and hollow carbon microspheres with reaction time of 36 and 72 h have the reversible capacities of 450,865,559 and 576 mAh/g during the galvanostatic discharge-charge experiments,and retain the capacities of 299,492,384 and 339 mAh/g after 50 cycles.The reversible capacity sequences of initial and 50th cycle by the shape of carbon microspheres are center grid＞ hollow＞ solid carbon microsphere.The shape of carbon microspheres has a great influence on the electrochemical performance of materials.The grid carbon microspheres show the best performance; and its specific capacity is more than graphite theory capacity of 372 mAh/g.