Nanocrystalline Manganese Iron Oxide as a Charge Storage Electrode

Abstract

Energy is one of the main issues in this century. The demand of energy for usage of modern electronic accessories has attracted lot of attention towards energy storage devices such as batteries and supercapacitors. Supercapacitors have the greater potential for providing good cyclability, high power density and energy density as compared with the batteries [1][2][3]. The synthesis of advanced electrode materials for charge storage is the key issue in the development of supercapacitors. It has been found that pseudocapacitors are more efficient than electric double layer capacitors (EDLCs) and exhibit 10 times more capacitance-per-unit surface area for a given electrode material [4]. The energy density and power density of pseudocapacitors are usually several times larger than those of EDLCs [5]. RuO 2 was the first candidate that was employed as a pseudocapacitor which exhibited a capacitance of about 700 F g À1 , however showed limited application due to its scarcity and high cost [6]. Recently, the approach of combining battery electrode materials and electrochemical supercapacitors known as hybrid electrochemical supercapacitors (HESC) is being studied. They have been studied both in aqueous and non-aqueous electrolytes. Advantage of non-aqueous medium being a wide operating potential window (upto~4 V) as compared to aqueous (~1 V) [7]. [43] have been studied for supercapacitor and HESC. Different methodologies for synthesizing binary oxide of distinct morphologies have been reported [33][34][35][36][37][38][39][40][41][42][43]. Morphology affects the chemical, physical and electrochemical properties of the material. Solution combustion synthesis has the advantage of producing fine and homogeneous powder of high purity in a single step self propagating process at low temperature with high exothermicity [44][45][46][47]. Citric acid is used as fuel as it is inexpensive and is a more effective complexing agent. It is often accompanied with the addition of certain amounts of NH 4 OH which help to overcome drying stresses and contribute to the porosity and strength of the solÀgel network [44]. In this present study manganese iron oxide Abstract: Phase pure nanocrystalline manganese iron oxide [(Mn 0.37 Fe 0.63 ) 2 O 3 ] was synthesized by combustion technique based on propellant chemistry principle employing citric acid as fuel. The synthesized powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET, BJH analysis and electrochemical studies for possible application as a charge storage electrode. The average crystallite size was found to be 18.6 nm from XRD analysis. BET analysis yielded the surface area and specific pore volume of the powder to be 22.96 m 2 g À1 and 0.0098 cm 3 g À1 respectively. The specific capacitance from cyclic voltammetric studies at scan rate 5 mV s À1 was found to be about 30 F g À1 cm À2 while from charge discharge studies was found to be 27 AE 1 Fg À1 cm À2. In addition, the material showed appreciable stability during charge-discharge cycling.

Carbon Encapsulated Ternary Mn−Ni−Co Oxide Nanoparticles as Electrode Materials for Energy Storage Applications

“…As described in the experimental section, the MnNiCoÀ O/C was synthesized by the simple calcination of the mixture of metal acetates-citrate complex, glucose and NaCl. In this study, NaCl particle surface was employed as the template for the nanosheets as it has a face-centered cubic crystal structure [35,36] and citric acid was used as a chelating agent for the metal ions [37]. The high temperature pyrolysis under N 2 followed by calcination at low temperature in air results in the formation of ternary MnNiCoÀ O/C hybrid nanostructure due to the thermal carbonization of glucose and oxidation of metal citrates.…”

All-Inorganic p−n Heterojunction Solar Cells by Solution Combustion Synthesis Using N-type FeMnO3 Perovskite Photoactive Layer

“…FeMnO 3 has been examined for applications such as lithium-ion batteries, catalysis, humidity sensors, energy storage and antibacterial devices ( Doroftei et al, 2014 ; Cao et al, 2016 ; Cetin et al, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ). A large number of synthesis methods, such as co-precipitation, hydrothermal, ball milling, solid state reaction and sol-gel chemistry, have all been employed for the fabrication of FeMnO 3 materials ( Sundari et al, 2013 ; Doroftei et al, 2014 ; Cao et al, 2016 ; Soni and Pal, 2016 ; Bin et al, 2017 ; Mungse et al, 2017 ; Gowreesan and Ruban Kumar, 2017 ; Saravanakumar et al, 2018 ; Cetin et al, 2019 ; Fix, 2019 ; Lobo and Rubankumar, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ; Vasiljevic et al, 2020b ). Despite this, not all these techniques are viable to synthesize FeMnO 3 nanomaterials, as there are some drawbacks such as the expense of the source materials, chemical non-uniformity, high impurity, aggregated nanoparticles, and non-stoichiometry of some ferrite systems ( Buonsanti et al, 2012 ; Alves et al, 2013 ; Bennet et al, 2016 ; Skliri, 2018 ).…”