scholarly journals A Redox-Mediator-Integrated Flexible Micro-Supercapacitor with Improved Energy Storage Capability and Suppressed Self-Discharge Rate

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3027
Author(s):  
Sung Min Wi ◽  
Jihong Kim ◽  
Suok Lee ◽  
Yu-Rim Choi ◽  
Sung Hoon Kim ◽  
...  
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Redox Reactions ◽  
Open Circuit Potential ◽  
Discharge Rate ◽  
Potential Drop ◽  
High Energy ◽  
Open Circuit ◽  
The Self ◽  
Gel Electrolyte

To effectively improve the energy density and reduce the self-discharging rate of micro-supercapacitors, an advanced strategy is required. In this study, we developed a hydroquinone (HQ)-based polymer-gel electrolyte (HQ-gel) for micro-supercapacitors. The introduced HQ redox mediators (HQ-RMs) in the gel electrolyte composites underwent additional Faradaic redox reactions and synergistically increased the overall energy density of the micro-supercapacitors. Moreover, the HQ-RMs in the gel electrolyte weakened the self-discharging behavior by providing a strong binding attachment of charged ions on the porous graphitized carbon electrodes after the redox reactions. The micro-supercapacitors with HQ gel (HQ-MSCs) showed excellent energy storage performance, including a high energy volumetric capacitance of 255 mF cm−3 at a current of 1 µA, which is 2.7 times higher than the micro-supercapacitors based on bare-gel electrolyte composites without HQ-RMs (b-MSCs). The HQ-MSCs showed comparatively low self-discharging behavior with an open circuit potential drop of 37% compared to the b-MSCs with an open circuit potential drop of 60% after 2000 s. The assembled HQ-MSCs exhibited high mechanical flexibility over the applied external tensile and compressive strains. Additionally, the HQ-MSCs show the adequate circuit compatibility within series and parallel connections and the good cycling performance of capacitance retention of 95% after 3000 cycles.

scholarly journals Limitations and Characterization of Energy Storage Devices for Harvesting Applications

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 783 ◽  
Author(s):  
Roberto de Fazio ◽  
Donato Cafagna ◽  
Giorgio Marcuccio ◽  
Paolo Visconti
Keyword(s):  
Energy Storage ◽  
Energy Harvesting ◽  
Voltage Drop ◽  
Discharge Rate ◽  
Open Circuit ◽  
The Self ◽  
Discharge Process ◽  
Energy Storage Devices ◽  
Time Duration ◽  
Storage Devices

This paper aims to study the limitations and performances of the main energy storage devices commonly used in energy harvesting applications, namely super-capacitors (SC) and lithium polymer (LiPo) batteries. The self-discharge phenomenon is the main limitation to the employment of SCs to store energy for a long time, thus reducing efficiency and autonomy of the energy harvesting system. Therefore, the analysis of self-discharge trends was carried out for three different models of commercial SCs, describing the phenomenon in terms of self-discharge rate and internal resistance. In addition, physical interpretations concerning the self-discharge mechanism based on the experimental data are provided, thus explaining the two super-imposed phenomena featured by distinct time constants. Afterwards, the dependence of self-discharge phenomenon from the charging time duration (namely, SCs charged at 5 V and then kept under charge for one or five hours) was analyzed; by comparing the voltage drop during the self-discharge process, a self-discharge reduction for longer charging durations was obtained and the physical interpretation provided (at best −6.8% after 24 h and −13.4% after 120 h). Finally, self-discharge trends of two commercial 380 mAh LiPo batteries (model LW 752035) were acquired and analyzed; the obtained results show an open circuit voltage reduction of only 0.59% in the first 24 h and just 1.43% after 124 h.

High energy density aqueous zinc–benzoquinone batteries enabled by carbon cloth with multiple anchoring effects

2021 ◽  
Author(s):  
Zhiqiang Luo ◽  
Silin Zheng ◽  
Shuo Zhao ◽  
Xin Jiao ◽  
Zongshuai Gong ◽  
...  
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Porous Carbon ◽  
Large Scale ◽  
High Energy ◽  
High Energy Density ◽  
Carbon Cloth ◽  
Anchoring Effects ◽  
High Theoretical Capacity ◽  
Energy Storage Applications

Benzoquinone with high theoretical capacity is anchored on N-plasma engraved porous carbon as a desirable cathode for rechargeable aqueous Zn-ion batteries. Such batteries display tremendous potential in large-scale energy storage applications.

scholarly journals Designing high energy density flow batteries by tuning active-material thermodynamics

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5432-5443
Author(s):  
Shyam K. Pahari ◽  
Tugba Ceren Gokoglan ◽  
Benjoe Rey B. Visayas ◽  
Jennifer Woehl ◽  
James A. Golen ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Energy Density ◽  
Fossil Fuels ◽  
Active Material ◽  
High Energy ◽  
Theoretical Framework ◽  
High Energy Density ◽  
Density Flow ◽  
The Cost

With the cost of renewable energy near parity with fossil fuels, energy storage is paramount. We report a breakthrough on a bioinspired NRFB active-material, with greatly improved solubility, and place it in a predictive theoretical framework.

scholarly journals Novel Lithium-Ion Capacitor Based on a NiO-rGO Composite

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3586
Author(s):  
Qi An ◽  
Xingru Zhao ◽  
Shuangfu Suo ◽  
Yuzhu Bai
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Power Density ◽  
High Power ◽  
Specific Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
Cycle Life ◽  
High Energy Density ◽  
Lithium Ion Capacitor

Lithium-ion capacitors (LICs) have been widely explored for energy storage. Nevertheless, achieving good energy density, satisfactory power density, and stable cycle life is still challenging. For this study, we fabricated a novel LIC with a NiO-rGO composite as a negative material and commercial activated carbon (AC) as a positive material for energy storage. The NiO-rGO//AC system utilizes NiO nanoparticles uniformly distributed in rGO to achieve a high specific capacity (with a current density of 0.5 A g−1 and a charge capacity of 945.8 mA h g−1) and uses AC to provide a large specific surface area and adjustable pore structure, thereby achieving excellent electrochemical performance. In detail, the NiO-rGO//AC system (with a mass ratio of 1:3) can achieve a high energy density (98.15 W h kg−1), a high power density (10.94 kW kg−1), and a long cycle life (with 72.1% capacity retention after 10,000 cycles). This study outlines a new option for the manufacture of LIC devices that feature both high energy and high power densities.

scholarly journals Nanocomposite multilayer capacitors comprising BaTiO3@TiO2 and poly(vinylidene fluoride-hexafluoropropylene) for dielectric-based energy storage

2014 ◽  
Vol 04 (02) ◽  
pp. 1450009 ◽  
Author(s):  
Mojtaba Rahimabady ◽  
Li Lu ◽  
Kui Yao
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Vinylidene Fluoride ◽  
Discharge Rate ◽  
Low Cost ◽  
Breakdown Field ◽  
High Discharge ◽  
High Discharge Rate ◽  
Poly Vinylidene Fluoride ◽  
Multilayer Capacitors

Multilayer dielectric capacitors were fabricated from nanocomposite precursor comprised of BaTiO 3@ TiO 2 core–shell nanosized particles and poly(vinylidene fluoride–hexafluoropropylene) (P(VDF–HFP)) polymer matrix (20 vol%). The multilayer capacitors showed very high discharge speed and high discharged energy density of around 2.5 J/cm3 at its breakdown field (~ 166 MV/m). The energy density of the nanocomposite multilayer capacitors was substantially higher than the energy density of commercially used power capacitors. Low cost, flexible structure, high discharge rate and energy density suggest that the nanocomposite multilayer capacitors are promising for energy storage applications in many power devices and systems.

scholarly journals Development on Thermochemical Energy Storage Based on CaO-Based Materials: A Review

2018 ◽  
Vol 10 (8) ◽  
pp. 2660 ◽  
Author(s):  
Yi Yuan ◽  
Yingjie Li ◽  
Jianli Zhao
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Energy Density ◽  
Circulating Fluidized Bed ◽  
High Energy ◽  
High Energy Density ◽  
Hydration Reaction ◽  
Initial Sample ◽  
Storage Performance ◽  
Low Activity

The intermittent and inconsistent nature of some renewable energy, such as solar and wind, means the corresponding plants are unable to operate continuously. Thermochemical energy storage (TES) is an essential way to solve this problem. Due to the advantages of cheap price, high energy density, and ease to scaling, CaO-based material is thought as one of the most promising storage mediums for TES. In this paper, TES based on various cycles, such as CaO/CaCO3 cycles, CaO/Ca(OH)2 cycles, and coupling of CaO/Ca(OH)2 and CaO/CaCO3 cycles, were reviewed. The energy storage performances of CaO-based materials, as well as the modification approaches to improve their performance, were critically reviewed. The natural CaO-based materials for CaO/Ca(OH)2 TES experienced the multiple hydration/dehydration cycles tend to suffer from severe sintering which leads to the low activity and structural stability. It is found that higher dehydration temperature, lower initial sample temperature of the hydration reaction, higher vapor pressure in the hydration reactor, and the use of circulating fluidized bed (CFB) reactors all can improve the energy storage performance of CaO-based materials. In addition, the energy storage performance of CaO-based materials for CaO/Ca(OH)2 TES can be effectively improved by the various modification methods. The additions of Al2O3, Na2Si3O7, and nanoparticles of nano-SiO2 can improve the structural stabilities of CaO-based materials, while the addition of LiOH can improve the reactivities of CaO-based materials. This paper is devoted to a critical review on the development on thermochemical energy storage based on CaO-based materials in the recent years.

scholarly journals High Energy Density Rechargeable Aqueous Lithium Batteries with an Aqueous Hydroquinone Sulfonic Acid and Benzoquinone Sulfonic Acid Redox Couple Cathode

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Hiroki Takagi ◽  
Koichi Kakimoto ◽  
Daisuke Mori ◽  
Sou Taminato ◽  
Yasuo Takeda ◽  
...  
Keyword(s):  
Energy Density ◽  
Sulfonic Acid ◽  
Acetic Acid Solution ◽  
Lithium Ion ◽  
High Energy ◽  
Open Circuit ◽  
Redox Couple ◽  
High Energy Density ◽  
Aqueous Acetic Acid ◽  
Ion Conducting

The demand for high energy density rechargeable batteries beyond lithium-ion batteries has increased for electric vehicles. In the present study, a novel high energy density rechargeable aqueous lithium battery was proposed. The battery was composed of a lithium metal anode, a lithium-stable non-aqueous electrolyte, a water-stable lithium-ion conducting solid electrolyte of Li1.4Al0.4Ge0.2Ti1.4(PO4)3-epoxy-TiO2 separator, and a hydroquinone sulfonic acid (HQS)/benzoquinone sulfonic acid (BQS) redox couple in an aqueous acetic acid solution (HAc). An open-circuit voltage of 3.7 V at 25 °C was recorded, and the theoretical energy density of the battery based on the reaction 2Li + BQS + 2H2O = 2 LiOH + HQS was 833 Whkg-1, about two times higher than that of the lithium-ion battery. The battery was successfully cycled at 0.5 mA cm-2 and 25 °C with low polarization.

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