Graphene–MnO2 and graphene asymmetrical electrochemical capacitor with a high energy density in aqueous electrolyte

Deng, Lingjuan; Zhu, Gang; Wang, Jianfang; Kang, Liping; Liu, Zong–Huai; Yang, Zupei; Wang, Zenglin

doi:10.1016/j.jpowsour.2011.09.005

Cited by 161 publications

(73 citation statements)

References 40 publications

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“…After activation, the value of R ct decreases obviously due to the presence of more active substances. A lower value of R ct corresponds to a higher supercapacitor SC [53]. The R ct value is lower after activation or after 8000 cycles, reflecting a higher SC, which is in good agreement with the cycle performance data.…”

Section: Samplesupporting

confidence: 85%

Three-dimensional graphene layers prepared by a gas-foaming method for supercapacitor applications

Hao

Liao

Zhong

et al. 2015

Carbon

106

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Section: Samplesupporting

confidence: 85%

Three-dimensional graphene layers prepared by a gas-foaming method for supercapacitor applications

Hao

Liao

Zhong

et al. 2015

Carbon

106

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“…The specific energy and power densities are also compared with values of other reported flexible asymmetric supercapacitors in Figure S11. [51][52][53][54] …”

Section: Electrochemical Performancesmentioning

confidence: 99%

Watchband‐Like Supercapacitors with Body Temperature Inducible Shape Memory Ability

Liu

Shen

Jiang

et al. 2016

Advanced Energy Materials

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shopping, detecting body-health, and so on. Nowadays, many major companies are working on exploring more functions on smart watches. In view of diverse functions of smart watches, there are increasing demands on their corresponding energy storage devices with high energy and/or power supply ability. [9][10][11][12][13] However, the energy storage devices are commonly placed in the watches with very small volume, which seriously limit their current energy storage ability and the future boost space. As we know, watchband is an important part of a watch and it plays the fixation function of the watch with a human wrist. Therefore, it can be imagined that, if the watchband had energy storage function, it might meet energy and/or power demands for the smart watches. Taking this into account, such smart watchband should have the right characteristics of flexible energy storage devices, including outstanding electrochemical performance, excellent flexibility, and good performance reliability while bending. In addition, good biocompatibility is a requirement for its practical application because of its direct touch with human skin.Supercapacitors are important energy storage devices, and they have attracted great attention for wearable electronic equipment due to their high power delivery ability, long cycle life, good safety as well as simple manufacturing. [14][15][16][17][18][19][20][21] Here, we demonstrate a new design and fabrication of flexible asymmetric supercapacitors with a smart "watchband-like" function, using reduced graphene oxide (rGO) coated on TiNi alloy (TNA) flake as the negative electrode, MnO 2 deposited on ultrathin Ni foil as the positive electrode, and aqueous or ion liquid-based gel electrolyte as the separator. TNA is a shape memory alloy (SMA) which can "remember" a presupposed shape at high temperature and it is free to bend and can hold the corresponding bending-shape below its phase transition temperature (PTT), and it can restore to the presupposed shape when the temperature is higher than its PTT. [22][23][24][25] In our study, as-made supercapacitors are able to possess excellent electrochemical capacitive properties, maintain the inherent characteristics of SMA (flexibility and shape recovery ability), and have outstanding electrochemical performance reliability while bending. Interestingly, because the PTT of TNA we used is 15 °C, the human skin temperature can directly actuate the shape recovery of the devices. Specifically, we use such a shape Smart watches have gained worldwide popularity because they can integrate diverse functions all in one. However, their energy storage devices currently being used are placed in the watches, and this design seriously limited the energy support ability and the future boost space. Herein, for the first time, a strategy to integrate energy storage device with watchband is put forward, which is realized by the preparation of watchband-like solid-state supercapacitors using graphene coated on TiNi alloy flake as the negative electrode, ultrathin MnO ...

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“…In general, CNTs, graphene, and highly graphitic carbons are attractive for this application because of the dramatic improvement in electrical conductivity of resultant MnO 2 composites. [28,38] However, the utilization efficiency and rate capability of MnO 2 are still big issues in most composites. Lei lent electrochemical performances, whereas the MnO 2 -based specific capacitance was only 280 F g À1 because of the high loading of MnO 2 (ca.…”

Section: Introductionmentioning

confidence: 99%

Hierarchically Porous Carbon with Manganese Oxides as Highly Efficient Electrode for Asymmetric Supercapacitors

Chou

Doong

et al. 2014

ChemSusChem

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A promising energy storage material, MnO2 /hierarchically porous carbon (HPC) nanocomposites, with exceptional electrochemical performance and ultrahigh energy density was developed for asymmetric supercapacitor applications. The microstructures of MnO2 /HPC nanocomposites were characterized by transmission electron microscopy, scanning transmission electron microscopy, and electron dispersive X-ray elemental mapping analysis. The 3-5 nm MnO2 nanocrystals at mass loadings of 7.3-10.8 wt % are homogeneously distributed onto the HPCs, and the utilization efficiency of MnO2 on specific capacitance can be enhanced to 94-96 %. By combining the ultrahigh utilization efficiency of MnO2 and the conductive and ion-transport advantages of HPCs, MnO2 /HPC electrodes can achieve higher specific capacitance values (196 F g(-1) ) than those of pure carbon electrodes (60.8 F g(-1) ), and maintain their superior rate capability in neutral electrolyte solutions. The asymmetric supercapacitor consisting of a MnO2 /HPC cathode and a HPC anode shows an excellent performance with energy and power densities of 15.3 Wh kg(-1) and 19.8 kW kg(-1) , respectively, at a cell voltage of 2 V. Results obtained herein demonstrate the excellence of MnO2 /HPC nanocomposites as energy storage material and open an avenue to fabricate the next generation supercapacitors with both high power and energy densities.

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Graphene–MnO2 and graphene asymmetrical electrochemical capacitor with a high energy density in aqueous electrolyte

Cited by 161 publications

References 40 publications

Three-dimensional graphene layers prepared by a gas-foaming method for supercapacitor applications

Three-dimensional graphene layers prepared by a gas-foaming method for supercapacitor applications

Watchband‐Like Supercapacitors with Body Temperature Inducible Shape Memory Ability

Hierarchically Porous Carbon with Manganese Oxides as Highly Efficient Electrode for Asymmetric Supercapacitors

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