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1.
《Current Applied Physics》2020,20(5):628-637
In this work, we have successfully synthesized MgNiO2 using a sol-gel wet chemical synthesis technique named MNO - 3. Electrochemical measurements in the presence of aqueous 1 M Li2SO4 electrolyte indicate that MNO - 3 samples exhibit a capacitance value of about 30 F/g and an energy density of about 20 Wh/kg. Subsequently, in the experiment involving aqueous 0.5 M Na2SO4 electrolyte system, it has been found that the capacitance for MNO - 3 sample is about 34 F/g and the energy density is about 23 Wh/kg for MNO - 3 sample. Finally, in the presence of aqueous-based 1 M Mg(ClO4)2 electrolyte, MNO - 3 sample is found to exhibit a capacitance of about 26 F/g and an energy density of about 17 Wh/kg, respectively. In all three electrolyte systems, the MNO -3 sample exhibit a long cycle capacitance retention of greater than 85% for 1000 charge-discharge cycles.  相似文献   
2.
In present investigation MnO2 thin films have been prepared by potentiodynamic (PD), potentiostatic (PS) and galvanostatic (GS) modes of electrodeposition. The effects of different modes on structural, surface morphological and supercapacitive properties of MnO2 thin films have been investigated. Formation of amorphous phase of MnO2 by all three modes is confirmed from X-ray diffraction (XRD) patterns. Significant change in the surface morphologies of MnO2 thin films due to different modes has been observed. The supercapacitive properties of MnO2 thin films have been studied in 1 M Na2SO4 electrolyte. The maximum supercapacitance obtained for potentiodynamic, potentiostatic and galvanostatic modes is 237, 196 and 184 F g−1, respectively. Additionally charge-discharge and impedance of MnO2 thin films have been investigated.  相似文献   
3.
采用固相法合成了纯六方相的TiS2粉体. X射线衍射(XRD)、扫描电子显微镜(SEM)结果表明该材料具有特征层状结构, 其颗粒大小在10-20 μm之间. 作为锂离子电池负极材料, TiS2在3.00 V(vs. Li+/Li)以下有3个明显的放电平台, 首次可逆容量达668 mAh·g-1, 在第一个放电电压范围(3.00-1.40 V)内具有优异的循环可逆性. 深度放电时由于Li2S的生成和材料颗粒严重破碎, 在低于0.50 V时材料的循环性能不佳. 通过减小材料颗粒度和提高导电剂含量, TiS2的电化学性能得到显著改善.  相似文献   
4.
石墨负极充放电过程的DFT研究   总被引:1,自引:0,他引:1  
用量子化学DFT-B3LYP/6-31G(d)方法计算了锂沿石墨层堆积的Zig-zag和Arm-chair方向嵌脱及在石墨表面附着和脱附的过程.结果表明,锂嵌入过程是体系能量升高的储能过程,势垒最高点是锂在碳原子正投影位置,即在C—C键投影位置,而在苯环中心投影位置最低,为嵌锂的最佳位置,锂嵌脱的最佳途径应为arm-chair方向;锂在石墨表面附着也是储能过程,苯环中心上方是石墨表面近距离附着机率最高的位置.  相似文献   
5.
《Current Applied Physics》2020,20(12):1404-1415
We report here the cost-effective synthesis of Magnesium Cobalt Oxide (MgCoO2) sample by the sol-gel synthesis route labeled as MCO - 3. In presence of aqueous 1 M Lithium Sulphate (Li2SO4) electrolyte, we obtained a capacitance of 56 F/g, an energy density of 38 Wh/kg and a capacitance retention of 92.53 % (at 5 A/g) after undergoing 1000 charge-discharge cycles. For the aqueous 1 M Sodium Perchlorate (NaClO4) electrolyte system, we found the capacitance, energy density and capacitance retention of 47 F/g, 31 Wh/kg and 91.41% (at 3.5 A/g for 1000 charge-discharge cycles), respectively. These results establish MgCoO2 as suitable electrode material in aqueous lithium-ion and sodium-ion supercapacitor devices. Further, MCO - 3 in the presence of aqueous 1 M Potassium Hydroxide (KOH) electrolyte showed an overpotential of 400 mV and a Tafel slope of 174 mV/dec, making it a suitable candidate for alkaline Hydrogen Evolution Reaction (HER) electrocatalyst.  相似文献   
6.
电池,尤其是锂离子电池的快速发展极大改变了我们的生活。从移动电子设备到新能源汽车再到电网储能,电池应用于多个领域且目前在能量密度和功率密度方面难以被取代。电池技术的向前发展要求我们对其电化学反应机理有完整的认识,这需要来自不同领域研究人员的交叉碰撞。磁共振波谱技术包括核磁共振波谱(NMR)和电子顺磁共振波谱(EPR),前者适合于研究Li、Na、P、O等电池材料中常见的轻元素,后者适合于研究Co、Mn、Fe、V等电池材料中常见的过渡金属。加上它们具有对样品无损、对结晶度无要求、能够定量分析等优点,NMR和EPR在过去三十年的电池研究中不断进步,日益成为电池表征的重要角色。本文从磁共振方法的角度出发,首先概述了固体NMR和EPR中的主要相互作用及其哈密顿表达形式,接着概述了固体NMR和EPR常用的重要方法及其在金属离子电池研究领域的代表性应用。本文有助于让我们直观地了解磁共振技术本身在金属离子电池研究领域的重要价值,并有望为解决利用固体NMR和EPR进行电池研究的过程遇到的困难提供指导。  相似文献   
7.
用恒电位法制成以9,10-蒽醌-2-磺酸钠盐(AQS)为掺杂阴离子的导电聚吡咯(PPy)电化学电容器电极材料,并采用循环伏安(CV)、充放电测试、电化学阻抗(EIS)等方法表征电容性质.结果表明,与高氯酸阴离子(ClO4-)掺杂的PPy相比,PPy/AQS电极材料不仅单位质量电容和电极稳定性得到提高,工作电压范围也得以扩大.在1mol·L-1的氯化钾中,工作电压为-0.6至0.6V,扫描速率为50mV·s-1时其单位质量电容达到491F·g-1,比PPy/ClO4-电极材料提高1.5倍.这是由于AQS自身良好的氧化还原活性和AQS掺杂有利于聚吡咯膜形成疏松多孔的纳米及亚微米颗粒结构而导致的.  相似文献   
8.
电解液流速对锌镍单液流电池性能的影响   总被引:1,自引:0,他引:1  
通过电化学测试、扫描电子显微镜观察和X射线衍射分析研究了电解液流速、电流密度和锌沉积面容量三者关系及对锌镍单液流电池充放电性能和负极锌沉积形貌的影响. 结果表明,锌沉积面容量是影响锌镍单液流电池充放电效率和负极锌沉积形貌的最主要因素,电解液流速不宜过高或过低. 随着锌沉积面容量的增大,电池的充放电效率和循环稳定性对电流密度的变化更为敏感,适宜的电解液流速范围变窄. 锌沉积面容量在25 mA·h/cm2以上,锌沉积皆呈海绵状. 在较低锌沉积面容量下,电解液流速也较低时,海绵锌沉积较为均匀致密. 而在高的锌沉积面容量下,海绵状锌沉积的团簇和颗粒变大,不均匀性加重,仅在适中的电解液流速(7.1 L/min)下,锌沉积部分致密规整,电池具有较好的充放电性能.  相似文献   
9.
Lithium nickelate (Li0.88Ni1.12O2), lithium cobaltate (LiCoO2) and lithium manganate (LiMn2O4) were synthesized by fast self-propagating high-temperature combustion and their phase purity and composition were characterized by X-ray diffraction and inductively coupled plasma spectroscopy. The electrochemical behaviour of these oxides was investigated with regard to potential use as cathode materials in lithium-ion secondary batteries. The cyclic voltammograms of these cathode materials recorded in 1 M LiClO4 in propylene carbonate at scan rates of 0.1 and 0.01 mV s–1 showed a single set of redox peaks. Charge-discharge capacities of these materials were calculated from the cyclic voltammograms at different scan rates. The highest discharge capacity was observed in the case of Li0.88Ni1.12O2. In all the cases, at a very slow scan rate (0.01 mV s–1) the capacity of the charging (oxidation) process was higher than the discharging (reduction) process. A strong influence of current density on the charge-discharge capacity was observed during galvanostatic cycling of Li0.88Ni1.12O2 and LiMn2O4 cathode materials. LiMn2O4 can be used as cathode material even at higher current densities (1.0 mA cm–2), whereas in the case of Li0.88Ni1.12O2 a useful capacity was found only at lower current density (0.2 mA cm–2). For the fast estimation of the cycling behaviour of LiMn2O4, a screening method was used employing a simple technique for immobilizing microparticles on an electrode surface. Electronic Publication  相似文献   
10.
Present work explored a room temperature, simple and low cost chemical route for the cobalt oxide film onto copper substrate from cobalt chloride (CoCl2·6H2O) precursor and characterization for its structural and electrochemical properties for supercapacitor application. The morphology and crystal structure of the film were investigated by scanning electron microscopy and X-ray diffraction techniques, respectively. The electrochemical supercapacitive properties of cobalt oxide film were evaluated using cyclic voltammetry and galvanostatic charge-discharge methods. The film showed maximum specific capacitance of (165 F/g) in 1.0 M aqueous KOH electrolyte at scan rate 10 mV/s.  相似文献   
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