A New Charge Storage Mechanism for Electrochemical Capacitors and Charge Storage Density Vs. Crystalline Structure of Metal Oxides

1995 ◽  
Vol 393 ◽  
Author(s):  
JP. Zheng ◽  
T.R. Jow

ABSTRACTThe hydrous ruthenium oxide (RuO2.xH2O) powders with different contents of H20 have been formed by a sol-gel process and have been annealed at different temperatures. It was found that the specific capacitance of RuO2.xH2O is strongly dependent on the crystalline structure. The specific capacitance of over 720 F/g was obtained in an amorphous RuO2.xH2O. This value is at least two times greater than ever reported of this type of material.The specific capacitance dropped rapidly as the amorphous phase transforms into the crystalline phase at high temperatures. In contrast to the crystalline phase the specific capacitance of an amorphous RuO2.xH2O was not dependent on the specific surface area. The charge storage mechanism in amorphous RuO2.xH2O is different from that in the crystalline RuO2. The current in the cyclic voltammetric curve of RuO2.xH2O is nearly constant and is symmetrical with the potential in a range of 1 volts. The resistivity of pellets made from these powders is in the order of 10−3 Ω-cm.

2019 ◽  
Vol 463 ◽  
pp. 513-525 ◽  
Author(s):  
Apurba Ray ◽  
Atanu Roy ◽  
Monalisa Ghosh ◽  
Jesús Alberto Ramos-Ramón ◽  
Samik Saha ◽  
...  

2021 ◽  
Vol 13 (6) ◽  
pp. 7135-7141 ◽  
Author(s):  
Brian M. Peterson ◽  
Cara N. Gannett ◽  
Luis Melecio-Zambrano ◽  
Brett P. Fors ◽  
Héctor Abruña

2016 ◽  
Vol 217 ◽  
pp. 1-8 ◽  
Author(s):  
Bao Zhang ◽  
Xiao Ji ◽  
Kui Xu ◽  
Chi Chen ◽  
Xiong Xiong ◽  
...  

2021 ◽  
Author(s):  
Xiangjun Pu ◽  
Dong Zhao ◽  
Chenglong Fu ◽  
Zhongxue Chen ◽  
Shunan Cao ◽  
...  

2020 ◽  
Author(s):  
Véronique Balland ◽  
Mickaël Mateos ◽  
Kenneth D. Harris ◽  
Benoit Limoges

<p>Rechargeable aqueous aluminium batteries are the subject of growing interest, but the charge storage mechanisms at manganese oxide-based cathodes remain poorly understood with as many mechanisms as studies. Here, we use an original <i>in situ</i> spectroelectrochemical methodology to unambiguously demonstrate that the reversible proton-coupled MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion is the main charge storage mechanism occurring at MnO<sub>2</sub> cathodes over a range of slightly acidic Al<sup>3+</sup>-based aqueous electrolytes. In Zn/MnO<sub>2</sub> assemblies, this mechanism is associated with high gravimetric capacity and discharge potentials, up to 560 mAh·g<sup>-1</sup> and 1.76 V respectively, attractive efficiencies (<i>CE</i> > 98.5 % and <i>EE</i> > 80%) and excellent cyclability (> 750 cycles at 10 A·g<sup>-1</sup>). Finally, we conducted a critical analysis of the data previously published on MnO<sub>x</sub> cathodes in Al<sup>3+</sup>-based aqueous electrolytes to conclude on a universal charge storage mechanism, <i>i.e.</i>, the reversible electrodissolution/electrodeposition of MnO<sub>2</sub>.<i></i></p>


Author(s):  
Cindy Soares ◽  
Begoña Silvan ◽  
Yong-Seok Choi ◽  
Veronica Celorrio ◽  
Giannantonio Cibin ◽  
...  

Here we report the synthesis via ceramic methods of the high-performance Mn-rich Na2.4Al0.4Mn2.6O7 oxygen-redox cathode material for Na-ion batteries which we use as a testbed material to study the effects...


1995 ◽  
Vol 393 ◽  
Author(s):  
T.R. Jow ◽  
J.P. Zheng

ABSTRACTRuthenium oxide thin films of an amorphous phase were successfully prepared on a titanium (Ti) substrate at temperatures below 160 °C. The sol-gel process using metal alkoxide precursor in nonaqueous solvents was used to prepare these films. The preliminary results showed that a specific capacitance of 430 F/g can be achieved for amorphous ruthenium oxide electrode in sulfuric acid. Films prepared by this method are compared with the films prepared by the thermal decomposition of the aqueous ruthenium chloride solution at temperatures above 300 °C. The specific capacitance, the crystalline structure, and the surface morphology of these films as a function of the preparation temperature were also discussed.


2017 ◽  
Vol 5 (44) ◽  
pp. 22939-22944 ◽  
Author(s):  
Xiaoying Niu ◽  
Guoyin Zhu ◽  
Zhihui Yin ◽  
Ziyang Dai ◽  
Xiaocheng Hou ◽  
...  

Schematic illustration of the fabrication process and charge storage mechanism of the hierarchical Ni wire/Co3O4@MnO2 nanowire array electrode.


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