Cashew Nut Shell Derived Porous Activated Carbon Electrodes for “Water‐in‐Salt” Electrolyte Based Symmetric Supercapacitor

Abstract

Biomass derived activated carbon has attracted well‐deserved attention in the realm of energy storage applications due to its high porosity and excellent electrochemical properties. In this study, cashew nutshell derived activated carbon (CNSAC) exhibits a highly interconnected and honeycomb like microporous structure with a large specific surface area of 835 m2 g−1 and a high pore volume of 0.4 m3 g−1. These superior structural features of CNSAC facilitate rapid diffusion of electrolyte and improve its electrochemical efficiency, which is desirable for electrode material. Fabrication of symmetrical supercapacitors (SSC) employing water in salt (WIS) electrolyte validates the outstanding electrochemical performance of CNSAC electrode material. WIS based SSC had a remarkable specific capacitance of 110 Fg−1 at a current density of 1 Ag−1 over a wider electrochemical stability window of 0–2 V, suggesting that WIS electrolytes can address the limitations of conventional aqueous electrolytes and have significant potential for diverse supercapacitor applications.

Highly Efficient Solid‐State Supercapacitor with Porous Electrode Material

“…However, the excessive addition of the activating agent led to structural collapse, which was evident from the SEM image of MSAC‐3‐700. [ 40 ] Moreover, the pores became more defined and well distributed with an increase in the carbonization temperature from 600 to 700 °C. Although there is a high degree of porosity; a further increase in temperature (800 °C) leads to the thinning of the structural walls of the MSAC.…”

“…Synthesis of MSAC: MSAC was prepared as previously described. [38,40] In this study, the chemical activation of the precursor was carried out using KOH as an activating agent at different activation ratios (weight ratio of mahogany fruit shell waste:KOH = 1, 2, and 3). Figure 1 represents the preparation of electrode materials.…”

Activated Carbon from Cashew Nut Husk and Cashew Nut Shell Wastes: Synthesis, Characterization, and Adsorption Studies

“…The cost of activated carbon (AC) derived from CNS has been projected to be lower than other crops, such as bamboo or coconut shells [8] . Not surprisingly, several publications in recent years have attempted to convert CNS into AC for high‐value applications [9,10] . AC is an amorphous material with a highly developed porous structure, large specific surface area, chemical inertness, and good mechanical stability, making it a commonly used component for formulating and compounding various commodity chemicals and materials [11,12] .…”

“…[8] Not surprisingly, several publications in recent years have attempted to convert CNS into AC for high-value applications. [9,10] AC is an amorphous material with a highly developed porous structure, large specific surface area, chemical inertness, and good mechanical stability, making it a commonly used component for formulating and compounding various commodity chemicals and materials. [11,12] The high adsorptive power of AC makes it desirable in wastewater treatment, air purification, energy storage, cosmetics, catalysis, and chemicals manufacturing industries.…”

Advances in Micro-/Mesopore Regulation Methods for Plant-Derived Carbon Materials

“…Plant materials are favored by researchers because they are more readily available in nature and have lower costs than animals and microorganisms. Carbon materials have been successfully prepared from natural plant materials (such as onion skin [ 15 ], rice husk [ 16 ], fruit peel, sawdust [ 17 ], lotus stem [ 18 ], nut shell [ 19 ] and seed [ 20 ]) and plant extracts (such as lignin [ 21 ], cellulose [ 22 ], sodium alginate [ 23 ] and glucose [ 24 ]). Some plant materials can maintain a more complete structure after carbonization and possess strong mechanical properties, which can be used directly as functional materials to simplify the preparation process.…”