摘要
用无定形TiO2与Li2CO3高温固相反应合成了性能良好的“零应变”电极材料Li4Ti5O12. XRD, SEM和激光粒度分析表明,产物结晶度好,无杂质相,为纯立方尖晶石相,Li4Ti5O12颗粒呈砾石状形貌,有团聚现象,平均粒度约2.66 mm. Li4Ti5O12电极具有较宽的充放电平台,循环性能稳定. 以0.1 C电流比率恒电流充放电,首次放电容量和循环容量分别达180和150 mAh/g. 交流阻抗谱研究发现,Li4Ti5O12不同嵌锂程度下的电导率对其电极的电化学阻抗具有较大影响,电极的Warburg阻抗曲线斜率与其荷电状态相关.
Micron-sized powder Li4Ti5O12 was prepared in a single-step solid state reaction involving amorphous TiO2 and Li2CO3, and its microcosmic characteristics and electrochemical behavior were studied. X-ray diffraction analysis indicated that the products of Li4Ti5O12 were of single cube-spinel phase structure with good crystallization. The laser particle size and scanning electron microscopy analysis showed uniformly distributed gravel Li4Ti5O12 particles with average grain size of 2.66 mm. The lithium cell, consisting of Li4Ti5O12 cathode and lithium anode, displayed a wide discharge/charge plateau at 1.5 V, a very stable characteristic for Li ion insertion and emission. The first discharge and cycle specific capacitance were 180 and 150 mAh/g at 0.1 C current respectively. AC impedance spectra of the Li/Li4Ti5O12 cell at charge/discharge potentials showed that electrochemical impedance was possibly influenced by the corresponding conductivity at the Li+ insertion extend, and the slopes of Warburg impedance lines were correlated with Li4Ti5O12 charge-states.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2005年第2期170-174,共5页
The Chinese Journal of Process Engineering
