碳包覆对水系磷酸钛钠电化学性能的影响  

Effect of carbon coating on the electrochemical properties of NaTi_2( PO_4)_3 in aqueous solution

作　　者：赵平[1,2] 申亚举 程杰[2,3] 文越华[2] 杨裕生[2,3] 

机构地区：[1]沈阳理工大学环境与化学工程学院,辽宁沈阳110159 [2]防化研究院,北京100191 [3]张家港智电芳华蓄电研究所有限公司,江苏张家港215600

出　　处：《现代化工》2016年第12期70-73,共4页Modern Chemical Industry

摘　　要：采用溶胶-凝胶法制备了纳米级磷酸钛钠(NaTi_2(PO_4)_3),以聚乙烯醇为碳源对其进行碳包覆,研究了碳包覆量对NaTi_2(PO_4)_3/C负极在硫酸钠水溶液中电化学性能的影响。结果表明,合成的NaTi_2(PO_4)_3材料为纳米级晶粒聚集而成。碳包覆量3.6%的NaTi_2(PO_4)_3/C电极表面包覆得较为均匀,表现出最佳的电化学性能。在高达4 C的倍率下,基于钠离子嵌入/脱出的首次放电比容量达到119 m Ah/g,循环20次后容量未见明显衰减,受析氢副反应等影响库仑效率缓慢降低,这与碳包覆表面的破坏,NaTi_2(PO_4)_3在水溶液中的结构变化有关。Sodium titanium phosphate（ NaTi2（PO4）3） anode materials are synthesized by sol-gel method and heat treatment in air. Polyvinyl alcohol is used as the carbon source to coat NaTi2（ PO4）3 by temperature-programmed calcination under nitrogen atmosphere. The crystalline structure and morphology of these materials are characterized by Xray diffraction and SEM. Electrochemical performance of the carbon coated NaTi2（ PO4）3with different carbon contents are investigated in 1. 0 mol / L Na2SO4 aqueous solution by using cyclic voltammetry and galvanostatic charge-discharge measurement. The results show that NaTi2（ PO4）3 exhibits about 80 nm of nano-sized crystalline with rhombohedral structure. The excellent electrochemical performance of the carbon coated NaTi2（ PO4）3 could be achieved with 3. 6% of carbon coating. The initial discharge capacity is 119. 0 m Ah / g and there is almost no capacity degradation after 20 cycles at a 4C rate charge-discharge. Butthe columbic efficiency degrades slowly with charge-discharge cycles.

关 键 词：磷酸钛钠 碳包覆 电化学性能 水溶液 

分 类 号：O646[理学—物理化学]