Hydrogels with highly concentrated salt solution as electrolytes for solid-state supercapacitors with a suppressed self-discharge rate

Shi, Mingwei; Yang, Wei; Zhang, Zailei; Zhao, Man; Wang, Zhong Lin; Lu, Xianmao

doi:10.1039/d1ta08709f

Cited by 18 publications

(5 citation statements)

References 54 publications

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“…This reduction is attributed to electron transfer impedance during electrolysis on account of increased formation of hydration clusters and reduced availability of free water molecules. Shi et al (2021) observed that the float currents reduced by 27 and 10.5 times at 0.8 and 1.6 V, respectively, when the concentration of LiCl increased from 1 to 14 M. Similar results were reported by Avireddy et al (2019) and Shi et al (2022).…”

Section: Addition Of Surfactantssupporting

confidence: 79%

Self‐discharge in supercapacitors. PartII: Factors influencing it and mitigation

Nimmakayala,

Srivastava,

Kumar

2024

WIREs Energy & Environment

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Supercapacitors have emerged as drivers for the advancement of green energy technologies in energy storage systems and energy‐efficient devices. Their ability to rapidly acquire and deliver charge at high current densities and long cycle life is key. However, their high self‐discharge rate prevents their potential use in a wide range of applications, especially when utilizing commonly available activated carbon electrodes. Addressing this bottleneck is hindered by the lack of a comprehensive understanding of the discharge process. In this review, we delve into a comprehensive review of factors (temperature, initial voltage, charging conditions, history, functional groups, pore geometry, and the impurities present) that influence self‐discharge in supercapacitors and attempts made in the literature on its mitigation (electrode, electrolyte, and separator modification).This article is categorized under: Emerging Technologies > Energy Storage

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Section: Addition Of Surfactantssupporting

confidence: 79%

Self‐discharge in supercapacitors. PartII: Factors influencing it and mitigation

Nimmakayala,

Srivastava,

Kumar

2024

WIREs Energy & Environment

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“…There have been approaches utilizing transformers, mechanical/electronic switches, and more recently, strategies for coupling charge pump circuits to BUCK circuits [52]. It is also possible to combine supercapacitors to store the energy collected by TENGs [53]. The utilization of energy management strategies for hydrogel-based TENGs is a perspective to drive their improvement.…”

Section: Hydrogel-based Tengs 21 Hydrogel-based Tengs For Energy Harv...mentioning

confidence: 99%

Hydrogel-Based Energy Harvesters and Self-Powered Sensors for Wearable Applications

Wang,

Li,

Zhang

et al. 2023

Nanoenergy Advances

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Collecting ambient energy to power various wearable electronics is considered a prospective approach to addressing their energy consumption. Mechanical and thermal energies are abundantly available in the environment and can be efficiently converted into electricity based on different physical effects. Hydrogel-based energy harvesters have turned out to be a promising solution, owing to their unique properties including flexibility and biocompatibility. In this review, we provide a concise overview of the methods and achievements in hydrogel-based energy harvesters, including triboelectric nanogenerators, piezoelectric nanogenerators, and thermoelectric generators, demonstrating their applications in power generation, such as LED lighting and capacitor charging. Furthermore, we specifically focus on their applications in self-powered wearables, such as detecting human motion/respiration states, monitoring joint flexion, promoting wound healing, and recording temperature. In addition, we discuss the progress in the sensing applications of hydrogel-based self-powered electronics by hybridizing multiple energy conversion in the field of wearables. This review analyzes hydrogel-based energy harvesters and their applications in self-powered sensing for wearable devices, with the aim of stimulating ongoing advancements in the field of smart sensors and intelligent electronics.

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“…It was worth mentioning that most hydrogel electrolyte based supercapacitor suffers from poor rate capability. 25,43,63 The outstanding rate performance in the supercapacitor with HE-NaClO 4 -15 is mainly attributed to the low R s with the iondiffusion rate in hydrogel electrolytes and low R ct with fast charge transfer between active electrode materials and the electrolyte. Comparing the electrochemical properties of three kinds of flexible supercapacitors, it is found that the CV curve of the supercapacitor assembled with HE-NaClO 4 -15 hydrogel electrolyte has the largest integrated area at a scanning speed of 100 mV s −1 (Figure S11a), which further verifies that the supercapacitor assembled with HE-NaClO 4 -15 hydrogel electrolyte has excellent rate performance.…”

Section: Rate Performances Of Supercapacitors Assembled With High-sal...mentioning

confidence: 99%

Low-Cost “Water-in-Salt” Hydrogel Electrolyte Enabled Flexible Supercapacitors with 2.7 V Voltage and −40 °C Adaptability

Yi,

Wu,

Zhou

et al. 2023

ACS Appl. Energy Mater.

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Aqueous electrolytes endow paramount safety for portable energy storage devices. However, they often suffer from narrow voltage windows and poor low-temperature performance.Here, a carrageenan/polyacrylamide double-network hydrogel electrolyte was synthesized by the one-pot method for highperformance supercapacitors. Instead of using the high-cost LiTFSI-based salt, three low-cost salts (NaNO 3 , LiNO 3 , and NaClO 4 ) were respectively added to the double-network electrolyte. By exploring the utmost dissoluble concentrations in the double-network hydrogel, we found that the concentration of NaClO 4 in the hydrogel satisfies the water-in-salt (WIS) criterion among the three hydrogel electrolytes, thus showing the best performance. The hydrogel electrolyte containing 15 mol L −1 NaClO 4 (HE-NaClO 4 -15) has an oxygen evolution potential broadened to 2.71 V and a high ionic conductivity of 10.3 mS cm −1 at −40 °C. The corresponding flexible symmetric supercapacitor exhibits a high operating voltage of 2.7 V and a specific energy density of 39.2 Wh kg −1 at a power density of 675 W kg −1 . In addition, the supercapacitor exhibits an impressive cycle life, and the capacitance retention is 90.9% after 20000 cycles at −40 °C. The supercapacitor works stably under mechanical abuse conditions. High voltage, stable electrochemical performance, and low-temperature operation make the supercapacitor adapt to the harsh working environment of portable energy storage devices.

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Hydrogels with highly concentrated salt solution as electrolytes for solid-state supercapacitors with a suppressed self-discharge rate

Abstract: Solid-state supercapacitors (SSSCs) using hydrogel electrolytes have attracted great interest in recent years due to their potential for powering flexible and wearable electronics. But the application of SSSCs has been...

Cited by 18 publications

References 54 publications

Self‐discharge in supercapacitors. PartII: Factors influencing it and mitigation

Self‐discharge in supercapacitors. PartII: Factors influencing it and mitigation

Hydrogel-Based Energy Harvesters and Self-Powered Sensors for Wearable Applications

Low-Cost “Water-in-Salt” Hydrogel Electrolyte Enabled Flexible Supercapacitors with 2.7 V Voltage and −40 °C Adaptability

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