Synthesis and electrochemical properties of ternary Co-, Cu- and Ni- based metal-organic frameworks electrode for battery supercapacitor hybrid application

Metal-organic frameworks (MOFs) composed by coordination bonds between metal ion with organic linker has a uniform combination of micro and mesoporous structures has been used for several application including battery supercapacitor hybrid. (BSH). In BSH, MOF offer several advantages including high surface area, porous, and structure tunability. This paper reports the synthesis of ternary MOF of copper (Cu), nickel (Ni) and cobalt (Co) with 1,4-benzenedicarboxylic acid. The Co/Cu/Ni-MOF is synthesized using hydrothermal method at 160 °C for 12h and further develop as a BSH electrode. The physicochemical properties of MOF were characterized using FESEM, FTIR, XRD, BET and the electrochemical properties were evaluated using cyclic voltammetry (CV), charge-discharge cycling (CDC) and electrochemical impedance spectroscopy (EIS). Electrochemical analysis indicated that the MOF has high specific capacitance (CS) of 591 F g-1 at a current density of 1 A g-1 and 519 F g-1 at scan rate of 2 mV s-1, and possess low series resistance (RS) of 0.44 Ω and equivalent distributed resistance (Rd) of 1.07 Ω

Large Scale Synthesis of Binary Composite Nanowires in the Mn2O3-SnO2 System with Improved Charge Storage Capabilities

Large scale production of electrochemical materials in non-conventional morphologies such as nanowires has been a challenging issue. Besides, functional materials for a given application do not often offer all properties required for ideal performance; therefore, a composite is the most sought remedy. In this paper, we report large scale production of a composite nanowire, viz. Mn2O3-SnO2, and their constituent binary nanowires by a large scale electrospinning pilot plant consisting of 100 needles. Electrochemical characterization of thus produced composite nanowires showed nearly threefold increase in the discharge capacity compared to their single component counterparts: Mn2O3-SnO2 ∼53 mA h g−1 (specific capacitance, CS ∼384 F g−1); Mn2O3 ∼18 mA h g−1 (CS ∼164 F g−1); and SnO2 ∼14 mA h g−1 (CS ∼128 F g−1) at 1 A g−1 in 6 M KOH. The EIS studies showed that the characteristic resistances and time of the composite electrode are appreciably lower than their constituents. Owing to the scalability of the synthesis processes and promising capacitive properties achieved would lead the composite material as a competitive low-cost and high-performance supercapacitor electrode

Synthesis and characterization of activated carbon from palm kernel shells for electrochemical double layer capacitor

Storage of electrical energy at an electrode–electrolyte interface under supercapacitive mode is intriguing owing to its large power capability compared to batteries. A large electrode surface is required for storing large amount of energy and high electrical conductivity of the electrode and electrolyte enable high rate delivery. Furthermore, primary material supply should be ensured for a research result to be adopted by industry. These requirements make carbons, in all of its allotropes, as a desirable candidate as an electrode material for supercapacitors. Biomass provides as an excellent source of carbon considering the renewability; however, properties of biomass even from similar species strongly vary depending on the geographical location. Malaysia is the largest exporter of palm oil; for each 2.5 kg of crude palm oil over 100 kg of biomass is produced as a byproduct. Palm oil produces six main biomass types such as fronds, trunks, empty fruit bunches, palm kernel shells (PKS), mesocarp fiber and palm oil mill effluent. Among them PKS contribute ~6%. However, use of PKS as a source of carbon for supercapacitors electrode has not been tested so far. This research thesis aims to evaluate the electrochemical properties of the carbon produced from PKS. Decomposition behavior of cleaned PKS was studied using thermogravimetric analysis and accordingly carbonized by pyrolysis. The as-prepared char was chemically activated using KOH, NaOH, H2SO4, and ZnCl2 in four impregnation ratios and optimized for the best surface properties. The structure and microstructure of the activated carbon were studied using X- ray diffraction and scanning electron microscopy, respectively. The electrochemical properties of all the sixteen samples obtained under various activation conditions were studied by cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy in a three-electrode system configuration using electrodes prepared from the PKS activated carbon (AC) as working electrode, Pt wire as counter electrode, and Hg/HgO as reference electrode in 1 M KOH electrolyte. The electrochemical properties were correlated with the surface properties in detail. Finally, a working supercapacitor is fabricated using the PKS AC electrodes developed on nickel foam substrate, glassy fiber as a separator, and 1 M KOH as electrolyte. The device delivered energy densities 6.6, 6.0, 5.7, 5.2, 4.5, 4.1, 3.5, 3.0 Wh/kg at power densities 60, 180, 310, 600, 1200, 1800, 300, 4000 W/kg, respectively. These values are comparable to the commercially available devices using activated carbon. Owing to the large abundance of carbon and promising results herewith, the present results show huge promise in developing PKS ACs as commercial supercapacitor electrodes

Conversion of Oil Palm Kernel Shell Biomass to Activated Carbon for Supercapacitor Electrode Application

Electrochemical charge storage of physically and chemically activated carbon synthesized from oil palm kernel shell (PKS) in three different aqueous electrolytes (1 M H2SO4, 1 M Na2SO4 and 6 M KOH) are presented. Coin type CR2032 cells fabricated using the PKS ACs electrodes separated by fiber glass separator and electrolyte are used as devices for measurements. Achievable operating potential for these devices varied as H2SO4 (1.0 V) < KOH (1.2 V) < Na2SO4 (2.0 V). The highest energy density was obtained in Na2SO4 electrolyte (7.4 Wh kg−1) at a power density of 300 W kg−1. The device stability cycle at low current density (0.5 A g−1) for 3500 times showed capacitance retention in range of 78–114% in all devices

Electrochemical Evaluation of Fluorinated MnO2 for Supercapacitor Application

Supercapacitors (SCs) functioning as alternative energy storage is useful in most electronic devices, renewable energy system and hybrid vehicles that have high demand in these days. Excellent electrochemical performance, environment friendliness and low cost material are needed to fulfil the energy demand by most developed country. In this study, fluorination treatment on manganese oxide (MnO2) is considered as an effective way to develop better energy storage due to fluorine electronegativity and reactivity when correlate with other element. Hydrothermal method is used to synthesis MnO2 (MnO2 and MnO2) and the effect of fluorination (FMnO2 and FMnO2) on MnO2 surfaces is investigated on the charge storage ability. The crystallinity and functional groups of the samples was confirmed by the X-ray diffractogram and fourier transforms infrared spectroscopy (FTIR). The cyclic voltammetry (CV) and galvanostatic charging–discharging (CDC) analysis in 0.5 M K2SO4 electrolyte shows that F--MnO2 gives the highest Cs value of 184 F g-1 at scan rate of 5 mV s-1 and 66 F g-1 at current density of 0.3 A g-1. The electrochemical impedance spectroscopy shows that the FMnO2 has the lowest electrode resistances and charge transfer resistance which contributes to high Cs and the high conductivity of electrode

Electrochemical Evaluation of Fluorinated MnO2 for Supercapacitor Application

Supercapacitors (SCs) functioning as alternative energy storage is useful in most electronic devices, renewable energy system and hybrid vehicles that have high demand in these days. Excellent electrochemical performance, environment friendliness and low cost material are needed to fulfil the energy demand by most developed country. In this study, fluorination treatment on manganese oxide (MnO2) is considered as an effective way to develop better energy storage due to fluorine electronegativity and reactivity when correlate with other element. Hydrothermal method is used to synthesis MnO2 (α–MnO2 and δ–MnO2) and the effect of fluorination (Fα–MnO2 and Fδ–MnO2) on MnO2 surfaces is investigated on the charge storage ability. The crystallinity and functional groups of the samples was confirmed by the X-ray diffractogram and fourier transforms infrared spectroscopy (FTIR). The cyclic voltammetry (CV) and galvanostatic charging–discharging (CDC) analysis in 0.5 M K2SO4 electrolyte shows that F-δ-MnO2 gives the highest Cs value of 184 F g-1 at scan rate of 5 mV s-1 and 66 F g-1 at current density of 0.3 A g-1. The electrochemical impedance spectroscopy shows that the Fδ–MnO2 has the lowest electrode resistances and charge transfer resistance which contributes to high Cs and the high conductivity of electrode

Effect of Organic Linkers on Metal-Organic Frameworks Electrode Fabrication for Battery Supercapacitor Hybrid Application

Metal organic framework (MOFs) of ternary metal precursors with different organic linkers are synthesized and fabricated on Ni-foam as the electrodes via hydrothermal reaction aiming to enhance the electrical conductivity and the specific capacitance, Cs. We report the preparation of ternary metal with different organic linkers named CoCuNi-bi using terephthalic acid (H2bdc), CoCuNi-tri using trimellitic acid and CoCuNi-tetra using pyromellitic acid with increasing of active sites on Ni-foam substrate respectively. The CoCuNi-tetra demonstrates the highest Cs of 740 F g-1 at 2 mV/s & 791 F g-1 (87.9 mAh g­­­-1) at 1 Ag-1 respectively followed by CoCuNi-tri (674 F g-1 at 1 A g-1; 74.9 mAh g-1) and CoCuNi-bi (591 F g-1 at 1 A g-1; 65.7 mAh g-1). CoCuNi-tetra shows the best electrochemical performance hence it could be the encouraging electrode for supercapacitor materials

Electrochemical Properties of Carbon from Oil Palm Kernel Shell for High Performance Supercapacitors

Electrochemical properties of activated carbon (AC) derived from oil palm kernel shell (PKS) are evaluated and compared with other biomass derived AC for fabricating high performance electrochemical double layer capacitors (EDLC). Cleaned PKS are carbonized by pyrolysis and subsequently activated by physical and chemical methods. The chemically AC show a wider pore distribution (1.49.3 nm) whereas the physically activated one has uniform pores (1.5 nm). The electrochemical properties of the two types of AC are evaluated using cyclic voltammetry (CV), charge–discharge cycling (CDC) and electrochemical impedance spectroscopy (EIS) in three-electrode configuration. High specific capacitance (CS) (210 F g-1 in 1 M KOH electrolyte at 0.5 A g-1) is obtained for chemically AC whereas the CS for the physically AC is 50% lower (123 F g-1). Galvanostatic CDC tests show that the electrodes maintained ~ 9597% of CS after 1000 cycles. The EIS revealed that the PKS AC has low series resistance (< 0.6 ) and relaxation time (~0.69 s) which would therefore offers high power density in the EDLC devices

High Performance Electrochemical Capacitor Based on Activated Carbon Derive from Palm Oil Kernel Shell

Carbon, in a number of polymorphic forms such as amorphous carbon, activated carbon, carbon fibers, carbon nanotubes, and graphere, is used as energy a storage material due to several reasons including low cost, abundant, stability and scalability

Void Space Control in Porous Carbon for High-Density Supercapacitive Charge Storage

High density charge (energy) storage under supercapacitive mode requires an electrode which would deliver larger space for charge accumulation and offer larger electrochemical potential difference at an electrode–electrolyte interface. Porous carbon has been a preferred electrode for commercial supercapacitors; however, the charge storability is much lower to the state-of-the-art charge storage devices such as lithium ion batteries. We show that one of the primary limiting factors is the voids in porous carbon, which do not contribute to the capacitance as their sizes are much larger than the size of the solvated/unsolvated ions in the electrolyte. We activate these voids by filling them with a flower-shaped 3D hierarchical pseudocapacitive material (MnCo2O4) by assuming that flower-shaped fillers would provide additional easily accessible surface for charge adsorption. Less than 10wt.% MnCo2O4 in these voids through a simple wet impregnation results in five-fold increase in charge storability of porous carbon from palm kernel shells. Laboratory prototypes of electrochemical double layer capacitors are fabricated using the void-filled-carbon electrodes, which show five-fold higher specific energy than that of pure carbon and are cycled over 5000 times with >95% capacitance retention. The present strategy of activating the voids by hierarchical 3D nanostructures could be applied to build high performance energy storage devices