Construction of shrimp shell (SS) waste-based carbon electrode-gel polymer electrolyte (GPE) system for flexible symmetric supercapacitors

Abstract

The development of environment-friendly and renewable energy storage devices is important to relieve energy pressure and reduce CO₂ emissions. In this research, hierarchical porous carbon electrodes and gel polymer electrolytes (GPE) based on shrimp shell (SS) waste were developed for the construction of flexible and symmetrical supercapacitor systems. A simple carbonization/activation approach was designed to obtain SS-based porous carbon with large specific surface area, interconnected hierarchical pore structure, and heteroatom doping. The SS porous carbon (SSKOH800) prepared at 800 °C KOH activation has a specific surface area of 1204.53 m² g⁻¹ and a specific capacitance of 356.23 F g⁻¹ (0.1 A) when used as an electrode material. Al³⁺ and HCl were co-crosslinked with SS waste-derived carboxylated chitosan (CYCTS) to prepare GPE (CYCTS-H⁺/Al–Li⁺) with good electrical conductivity and mechanical stability. The flexible symmetrical device (CYCTS-H⁺/Al–Li⁺//SSKOH800) showed a high energy density of 26.71 W h kg⁻¹ at a power density of 250 W kg⁻¹ and a cycle stability of over 90% at 5000 charge/discharge cycles. In addition, the flexible device maintains good capacitive behavior at different folding angles. This work demonstrates the potential use of electrode-GPE supercapacitor systems prepared from SS waste in future wearable and portable electronic devices and provides ideas for the development of different types of energy storage components based on a sustainable, readily degradable biomass.