Effect of KOH Activator on the Performance of Activated Carbon from Oil Palm Kernel Shell as Supercapacitor Electrode Material

Abstract

Karbon aktif dari cangkang kelapa sawit sebagai bahan elektroda superkapasitor telah diteliti. Superkapasitor dirangkai dengan metoda plat/sandwich yang dipisahkan oleh separator. Untuk mendapatkan nilai kapasitansi yang besar dilakukan variasi jumlah aktivator terhadap karbon menggunakan aktivator KOH. Sifat fisikokimia dari karbon aktif diteliti dengan melakukan karakterisasi menggunakan XRD (X-Ray Diffraction), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-Ray) dan SAA (Surface Area Analyzer) dan sifat elektrokimianya diteliti dengan pengukuran CV (Cyclic Voltammetry). Karbon aktif dengan perbandingan 1:5 memiliki luas permukaan yang paling besar yaitu 793,326 m2/g dan nilai kapasitansi spesifik tertinggi yaitu 99,151 F/g. The activated carbon from oil palm kernel shell as an electrode material for supercapacitors has been investigated. The supercapasitor was assembled by plate/sandwich methods. Both electrodes were separated by using a separator. To increase the capacitancy value, variations in the number of activators on carbon were carried out using KOH activator. The physicochemical properties of activated carbon were investigated by characterizing using XRD (X-Ray Diffraction), SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-Ray) and SAA (Surface Area Analyzer) and the electrochemical properties were investigated by measuring CV (Cyclic Voltammetry). Activated carbon with a ratio of 1:5 has the largest surface area of 793,326 m2/g and the highest specific capacitance value is 99,151 F/g.Keywords: activated carbon, supercapasitor, activator, surface area, specific capacitance

An Evaluation of the Reliability of the Results Obtained by the LBET, QSDFT, BET, and DR Methods for the Analysis of the Porous Structure of Activated Carbons

“…In recent years, potassium hydroxide KOH, which is a strong base that diffuses into the carbon layers and destroys the texture structure of a raw material creating microporosity in the carbon structure, is becoming increasingly popular as an activating agent [ 16 , 17 ]. Zinc chloride is the most effective activator in the processes for obtaining activated carbons, making it possible to prepared activated carbons with a very well-developed pore structure and a narrow range of microporosity without the participation of mesopores.…”

“…Zinc chloride is the most effective activator in the processes for obtaining activated carbons, making it possible to prepared activated carbons with a very well-developed pore structure and a narrow range of microporosity without the participation of mesopores. Potassium hydroxide is more effective as an activator than its alternatives due to the formation of the free element K during the activation process and its intercalation in the structure of hexagonal planes built of carbon atoms [ 16 , 17 ]. The metallic potassium intercalated into the carbon material structures is removed in the subsequent HCl washing process, because of which voids are formed in the structure of the material.…”

“…However, this compound is not completely evaporated during the activation process because its boiling point is 1600.15 K—much higher than the activation temperature. Therefore, it is very important to thoroughly wash the activated carbons obtained in the KOH activation process with water [ 16 , 17 ]. Due to its potential threat to the natural environment, potassium hydroxide is increasingly being replaced with potassium carbonate K 2 CO 3 .…”

“…Activated carbons are produced from the process of physical activation preceded by carbonization or through the process of chemical activation [8][9][10][11][12][13][14][15][16][17]. However, these processes must be preceded by pre-processing of the precursor, including the stages of washing, drying, crushing, and milling, as well as sieving to the appropriate grain fraction.…”

“…The production of activated carbons by chemical activation consists of a one-step reaction of the raw material with an activating agent [11][12][13][14][15][16][17]. In the process of chemical activation, the raw material is first mixed or impregnated with a chemical compound-potassium hydroxide KOH, potassium carbonate K 2 CO 3 , phosphoric(V) acid H 3 PO 4 , sulphuric acid H 2 SO 4 , or zinc chloride ZnCl 2 .…”