Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated....Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity （120 mAh/g） at a discharge rate of 0.2 C （29.6 mA/g）. The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73~ at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.展开更多
Li1±xNi0.5Mn1.5O4(x=0.05,0) spinel powders were synthesized using a solid-state reaction.Their structures were characterized by X-ray diffraction,scanning electron microscopy and Raman spectroscopy.Their electroc...Li1±xNi0.5Mn1.5O4(x=0.05,0) spinel powders were synthesized using a solid-state reaction.Their structures were characterized by X-ray diffraction,scanning electron microscopy and Raman spectroscopy.Their electrochemical properties for use as active cathode materials in lithium-ion batteries were measured.The LiNi0.5Mn1.5O4,Li1.05Ni0.5Mn1.5O4 and Li0.95Ni0.5Mn1.5O4 samples crystallized in Fd 3m,Fd 3m and P4332,respectively.The LiNi0.5Mn1.5O4 and Li0.95Ni0.5Mn1.5O4 samples exhibited better cycle performance than the Li1.05Ni0.5Mn1.5O4 sample,while Li0.95Ni0.5Mn1.5O4 had the worst rate performance.Thus,it appears unnecessary to introduce nominal lithium nonstoichiometry in LiNi0.5Mn1.5O4 electrode materials.展开更多
基金supported by the National Natural Science Foundation for Postdoctoral Scientists of China (Grant No. 20090451554)
文摘Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity （120 mAh/g） at a discharge rate of 0.2 C （29.6 mA/g）. The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73~ at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.
文摘稻壳基活性炭(RH-AC)具有天然的多级孔道结构,是由稻壳碳化和活化两步得到的。用RH-AC和锰酸锂(LMO)混合制备复合电极,以锂片为对电极,组装半电池进行恒流充放电测试。实验发现:含有质量分数为5%的RH-AC与90. 5%的LMO的复合电极(RH-AC5)在5C电流密度循环100圈后比容量为89. 3 m A·h/g,容量保持率高于89%,远优于纯锰酸锂电极。采用循环伏安法计算出的锂离子扩散系数,及利用交流阻抗测试拟合后得到的结果进一步验证了该结论。
基金supported by the National Natural Science Foundation of China (20971117 and 10979049)the Education Department of Anhui Province (KJ2009A142)
文摘Li1±xNi0.5Mn1.5O4(x=0.05,0) spinel powders were synthesized using a solid-state reaction.Their structures were characterized by X-ray diffraction,scanning electron microscopy and Raman spectroscopy.Their electrochemical properties for use as active cathode materials in lithium-ion batteries were measured.The LiNi0.5Mn1.5O4,Li1.05Ni0.5Mn1.5O4 and Li0.95Ni0.5Mn1.5O4 samples crystallized in Fd 3m,Fd 3m and P4332,respectively.The LiNi0.5Mn1.5O4 and Li0.95Ni0.5Mn1.5O4 samples exhibited better cycle performance than the Li1.05Ni0.5Mn1.5O4 sample,while Li0.95Ni0.5Mn1.5O4 had the worst rate performance.Thus,it appears unnecessary to introduce nominal lithium nonstoichiometry in LiNi0.5Mn1.5O4 electrode materials.
