石墨型C_3N_4的固态合成及嵌锂性能研究

Solid-state Synthesis of Graphite-like C_3N_4 and Its Reversible Li^+ Intercalation

采用固态反应方法制备了石墨型C3N4.采用XRD,FTIR,XPS对产物的组成和结构进行了表征.研究了石墨型C3N4的电化学行为,并将其用作负极材料组装成锂离子电池进行测试,发现该材料具有一定的嵌锂能力,但比容量低,循环寿命短.采用少量嵌入Mg2+,Al3+的方法对石墨型C3N4进行改性,结果发现石墨型C3N4的充放电性能得到一定改善.

Graphite-like carbon nitride （g-C3N4） was synthesized using a solid state method and characterized by XRD, FTIR and XPS. The electrochemical properties of the g-C3N4 were studied using both cyclic voltammetry and charge-discharge cycling. It was found that the g-C3N4 sample showed certain reversible intercalation capacity of Li^＋, but the capacity dropped sharply during the first few cycles. The poor reversibility could be ascribed mainly to the decomposition of C3N4 upon electroreduction. Modification of the g-C3N4 was performed by intercalating a little amount of Mg^2＋ and Al^3＋ into its interlayer spacing, which made slight improvement on the crystallization and the reversible Li^＋ intercalation of the residual g-C3N4.