A Biodegradable Gel Electrolyte for Use in High-Performance Flexible Supercapacitors

Abstract

Despite the significant advances in solid polymer electrolytes used for supercapacitors, intractable problems including poor ionic conductivity and low electrochemical performance limit the practical applications. Herein, we report a facile approach to synthesize a NaCl-agarose gel electrolyte for use in flexible supercapacitors. The as-prepared agarose hydrogel consists of a three-dimensional chemically interconnected agarose backbone and oriented interparticular submicropores filled with water. The interconnected agarose matrix acts as a framework that provides mechanical stability to the gel electrolyte and hierarchical porous networks for optimized ion transport. The developed pores with the water filler provide an efficient ionic pathway to the storage sites of electrode. With these properties, the gel electrolyte enables the supercapacitor to have a high specific capacitance of 286.9 F g(-1) and a high rate capability that is 80% of specific capacitance obtained in the case of a liquid electrolyte at 100 mV s(-1). In addition, attributed to the simple procedure and its components, the gel electrolyte is highly scalable, cost-effective, safe, and nontoxic. Thus, the developed gel electrolyte has the potential for use in various energy storage and delivery systems.

Design Considerations for Unconventional Electrochemical Energy Storage Architectures

“…Yin et al fabricated recently a fully biodegradable primary batteries making use of bioresorbable building blocks [ 774 ] whereas a biodegradable gel electrolyte for fl exible supercapacitors was proposed by Moon. [ 775 ] Berchmans et al were the fi rst to report the fabrication of a rechargeable, benign, skin-worn Ag/Zn-based tattoo battery by making use of unconventional materials, such as screen printed electrodes, temporary tattoo paper, alkaline gel electrolytes and a PDMS cover for sealing the battery. [ 776 ] Although several advances have been made towards this end, the route yet is long before naturally powering up a Li-ion battery.…”

Multi‐walled carbon nanotubes incorporation into cross‐linked novel alkaline ion‐exchange membrane for high efficiency all‐solid‐state supercapacitors

“…Furthermore, Figure 5B shows a negative correlation between the capacitance and the current density, that is, a higher current density acquisitions the smaller capacitance value, this is due to the low-utilization and increasing charge resistance of the active material when the charge-discharge current density is too large. 63,64 However, upon increasing the current density to 14 A g −1 , the specific-capacitance retained 67% of the pristine capacitance value, corresponding to 18.38 mF cm −2 .…”

Advances in Flexible and Wearable Energy‐Storage Textiles

“…Electrodes can be either active materials attaching to current collectors or freestanding active materials, and the capability of storing energy majorly depends on the properties of active materials. Electrolytes are usually solutions with desired ionic conductivity, while recently more and more researchers are focusing on hydrogel electrolytes (quasi‐solid‐state) and solid‐state electrolytes, as the elimination of liquid may help to address the safety issues caused by toxic and flammable solutions, raise the cycle stability, avoid electrolyte leakage, and erase the necessity of separators . Separators are used to separate two electrodes; otherwise, contact of the electrodes will lead to short circuit.…”