Cr^(3+)掺杂锰酸锂薄膜电极的溶胶凝胶制备方法

Cr^(3+) doped LiMn_2O_4 thin film cathode electrodes prepared by Sol-gel method

以锂、锰和铬的硝酸盐为原料,乙二醇为溶剂,采用Sol-gel方法在SUS304不锈钢表面制备了Cr^(3+)掺杂的锰酸锂正极薄膜。通过X射线衍射、扫描电子显微镜、循环伏安、交流阻抗及恒电流充放电测试等方法对薄膜结构及电化学性能进行了表征分析,并探索Cr^(3+)掺杂对锰酸锂循环性的影响。研究结果表明,在电压3.2~4.3V、测试电流0.1mA/cm^2的条件下,由于晶体结构的稳定性得到提高,LiCr_(0.2)Mn_(1.8)O_4薄膜表现出良好的循环稳定性,在25℃和55℃条件下600圈后其容量保持率分别为84%和83%,而在与本实验相同条件下未掺杂LiMn_2O_4(LMO)薄膜的容量保持率仅为54%和39%。通过该溶胶凝胶技术制备的薄膜电极可应用于微电子领域薄膜电池或全固态电池。

The Cr-doped lithium manganese oxide thin-film cathodes were deposited on the stainless steel(SUS304)substrate by sol-gel method using lithium nitrates,manganese nitrates and chromium nitrates as the precursors and ethylene glycol as the chelating agent for Li-ion battery.The as-synthesized film cathodes were characterized by X-ray diffraction,scanning electron microscopy,cyclic voltammetry,AC impedance and charge-discharge testing.The effect of Cr-doping on the electrochemical performance of the as-synthesized film was also studied.The results showed that LiCr_(0.2)Mn_(1.8)O_4 thin-film presented better cycle performances owing to the improvement of the stability of the crystal structure.After 600 cycles,the capacity retention ratios were 84% and 83% at 25 ℃ and 55 ℃,respectively,at the current density of 0.1 mA/cm^2 and the voltage of 3.2-4.3 V.While that of the undoped LiMn_2O_4 thin-film were only 54% and 39%,respectively,in the same condition.The thin film electrode synthesized by Sol-gel technology can be used for thin film battery or all-solid-state battery in the microelectronic field.