摘要
采用双氧水氧化辅以水热法制备α-Mo O3纳米带正极材料,用XRD和SEM对结构和表面形貌进行分析,用循环伏安法和恒流充放电研究电化学性能。在200℃水热条件下制备的α-Mo O3纳米带呈板条状;在180℃下制备的呈细条带状。α-Mo O3首次循环伏安曲线上出现的两对还原氧化峰（2.73 V、3.06 V）和（2.24 V、2.74 V）,分别对应于Li＋在α-Mo O3八面体层内的不可逆嵌脱和层间的可逆嵌脱。以0.2 C在1.5-3.5 V充放电,板条状和长条状α-Mo O3纳米带的首次放电比容量分别为294.7 m Ah/g和300.0 m Ah/g,50次循环的容量保持率分别为49.9%和63.4%。给出了α-Mo O3的充放电机理,发现容量衰减主要是Li＋在α-Mo O3八面体层内的不可逆脱嵌引起的。
α-MoO3 nanobelts were synthesized by hydrogen peroxide oxidation and hydrothermal method. The structure and morphology were analysized by XRD and SEM, electrochemical performance was studied by cyclic voltammetry and galvanostatic charge-discharge. The orthorhombic α-MoO3 nanobelts synthesized by hydrothermal method at 200℃ showed strip form, the ones prepared at 180℃ showed fine ribbon form. Two pairs of redox peaks at 2. 73 V,3.06 V and 2. 24 V,2. 74 V which were appeared on the initial cyclic voltammetry curve of or-MoO3, were attributed to the irreversible Li^＋ intercalation/de-intercalation in octahedron intralayers of or-MoO3 and the reversible insertion/extraction in interlayers, respectively. When charged-discharged in 1.5 - 3.5 V at 0. 2 C,the initial specific discharge capacity of strip form and fine ribbon form α-MoO3 at 0. 2 C was 294. 7 mAh/g and 300. 0 mAh/g, respectively, the capacity retention after 50 cycles was 49. 9% and 63.4%, respectively. The charge-discharge mechanism of α-MoO3 was given,it was found that the capacity fading was mainly attributed to the irreversible Li^＋ intercalation/de-intercalation in α-MoO3 octahedron intralayers.
出处
《电池》
CAS
CSCD
北大核心
2015年第5期269-272,共4页
Battery Bimonthly
基金
中国矿业大学实验室开放基金(2014203)
关键词
α-MoO3纳米带
水热法
电化学性能
充放电机理
α-MoO3 nanobehs
hydrothermal method
electrochemical performance
charge-discharge mechanism
