LiNiPO_4前驱体固相反应合成动力学及电容性能  

The Process Reaction Kinetics of Synthesis and Capacitance Performance of LiNiPO_4 from a Precursor via Solid-State Reaction

作　　者：黄映恒[1,2] 童张法[1] 廖森[1] 蓝建京[1] 

机构地区：[1]广西大学化学化工学院,广西南宁530004 [2]桂林理工大学南宁分校冶金工程系,广西南宁530001

出　　处：《北京理工大学学报》2011年第7期872-877,共6页Transactions of Beijing Institute of Technology

基　　金：国家自然科学基金资助项目(20766001);广西青年科学基金资助项目(0728101);广西教育厅基金资助项目(200505083)

摘　　要：以氢氧化锂、磷酸二氢铵和醋酸镍为原料,以聚乙二醇PEG-400为表面活性剂,采用前驱体固相活化法制备LiNiPO4纳米晶材料.固相制备过程的活化能E=81.08 kJ·mol-1,过程动力学为二维相界面扩散反应机理.前驱体生成LiNiPO4的反应符合界面反应指数成核机理,活化能E1=11.82 kJ·mol-1,指前因子lnA=13.82;LiNiPO4晶体生长过程具有较小的活化能E2=17.73 kJ·mol-1;Li3PO4转化反应和反应体系物系晶化过程符合二维相界面扩散反应机理,其是制备过程可控制的重要步骤.材料复合电极LiNiPO4+Nafion/C在0.5 mol·L-1H2SO4中具有典型的电容性能,电极比电容为214 F·g-1,经1 000次循环,电极电容量不但没有衰减反而略有增加,是潜在的电容器材料.The nano-erystallite LiNiPO4 powder was synthesized via solid-state reaction of the precursor NH4NiPO4 using raw materials LiOH, NH3H2PO4 and NiAc2 · 4H2O by adding surfactant PEG-400. The results showed that the process kinetics mechanism of LiNiPO4 crystals was two-dimensional interface diffusion and the reaction activation energy E was 81.08 kJ · mol^-1. The formation of amorphous LiNiPO4 from the precursor consists with the interracial reaction mechanism of the index nucleation which the activation energy E1 was 11.82 kJ · mol^-1 and logarithm of exponential factor in A was 13. 82. The process of crystal LiNiPO4 growth had smaller activation energy E2 of 17.73 kJ · mol^-1. The key controllable steps in whole prepared processes are the conversion reaction and crystallization of LiNiPO4. LiNiPO4 ＋Nafion/ C composite electrode in sulfuric acid solution （0.5 mol · L^-1 ） has typical capacitance properties and the specific discharge capacity was 214 F · g^- 1 After 1 000 times discharge and charge cycling, the electrode discharge capacity increased slightly instead of attenuation. Results show that the LiNiPO4 ＋Nafion/C composite could be applied as the potential material for capacitor.

关 键 词：LiNiPO4 含锂磷酸盐 固相反应 超电容性 

分 类 号：O643[理学—物理化学] TQ131.11[理学—化学]