液相无焰燃烧法制备尖晶石型LiNi_(0.08)Mn_(1.92)O_4及其电化学性能

通过液相无焰燃烧法制备了尖晶石型LiNi_(0.08)Mn_(1.92)O_4正极材料,采用XRD、SEM、循环伏安、交流阻抗及恒电流充放电测试等手段,分析了温度对产物晶体结构、微观形貌及电化学性能的影响。XRD结果表明掺Ni后的LiMn_2O_4仍为单一的尖晶石结构物相。SEM结果表明Ni掺杂改善了材料的形貌,稳定了材料的结构。电化学测试表明:700℃制备的LiNi_(0.08)Mn_(1.92)O_4电化学性能较优,在1C下初始放电比容量为105.0mAh·g~(-1),Rct值最小为135.6Ω,表明在电化学反应期间锂的嵌入和脱出引起的动力学阻抗最小;在0.5C~10C倍率循环中,700℃的样品比容量恢复率明显要高于其他温度的样品,表现出较好的循环可逆性和倍率循环稳定性。

Prepared and electrochemical properties of Spinel LiNi 0.08Mn1.92O4 by a Liquid-phase flameless combustion method

Spinel LiNi0.08Mn1.92O4cathode material were synthesized via a liquid-phase flameless combustion method.The effects of calcination temperature on structure,morphology and elec-trochemical performance of the powders were studied by X-ray diffraction,scanning electron mi-croscopy,CV,EIS and galvanostatic charge-discharge test.XRD spectra indicated that Ni-doped LiM n2O4is still a single spinel structure phase.SEM pattern indicate that Ni-doped improves the morphology and stabilizes the structure of the materials.The electrochemical test showed that the powder calcined at 700 ℃ deliver a relatively superior electrochemical performance with an in-itial discharge capacity of 105 mAh·g -1at 1 C and the minimum value of Rct is 135.6Ω,which indicates that the kinetic impedance was minimal during intercalation and deintercalation with electrochemical reaction.In the 0.5 C~10 C rate cycle,the capacity recovery rate of the sample at 700℃ was significantly higher than other sample,and it showed good cycle reversibility and magnification cycle stability.