摘要
以KMnO_4、HCl为反应物,H_2SO_4、NH_4Cl为助剂,利用水热法成功合成了α-MnO_2纳米管自组装微球。并采用X射线晶体衍射(XRD)、场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)以及X射线光电子能谱(XPS)表征手段对产物进行了形貌和结构表征,发现H^+与Cl-离子浓度对产物的晶型有很大影响:单一增加H+或Cl-离子浓度可以使纳米管管径减小、长度增加;同时增加两种离子浓度则产物从α相转化为β相;NH4+可以起到维持产物晶型(α相)以及管状形貌的作用。电化学性能测试表明,具有独特形态的α-MnO_2纳米管微球作为锂电负极具有高容量(20 m A·g-1电流密度下首周放电比容量达1783.5 m Ah·g-1)与良好的倍率性能,是具有广阔应用前景的锂离子电池材料。
Self-assembled microspheres of a-MnO2 nanotubes were successfully synthesized by hydrothermal method using KMnO4 and HCI as reactants, and H2SO4 and NH4Cl as auxiliaries. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and X-ray photoelectron spectroscopy （XPS） were used to characterize the structure and morphology of the products. The H＋ and Cl- ion concentrations substantially influence the crystal form of the product. Increasing either H＋ or CI- ion concentration decreases the diameter of nanotubes but increases their length. In contrast, increasing both H＋ and Cl- ion concentrations, changes the product from a phase to β phase. Moreover, NH4＋ ion plays the key role of maintaining the product crystal and its tubular morphology The electrochemical performance results showed that the microspheres of α-MnO2 nanotubes with a unique morphology have a high first cycle discharge capacity of 1783.5 mAh.g-1 at the current density of 20 mA.g-1, along with a good rate performance. This suggests that the self-assembled microspheres were a promising material for lithium-ion batteries.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2017年第7期1421-1428,共8页
Acta Physico-Chimica Sinica
基金
国家重点研发计划(2016YFB0901502)
国家自然科学基金(21231005
51371100)资助项目~~
关键词
α-MnO2纳米管
可控制备
自组装微球
水热合成法
锂离子电池
α-Mn02 nanotubes
Controllable preparation
Self-assembled microspheres
Hydrothermal synthesis
Lithium-ion battery
