Synthetic Metals 162 (2012) 1303–1307 Contents lists available at SciVerse ScienceDirect Synthetic Metals journa l h o me page: www.elsevier.com/locate/synmet Wet-chemical polyaniline nanorice mass-production for electrochemical supercapacitors ShoyebMohamad F. Shaikh a , Ji Yeon Lim a , Rajaram S. Mane b , Sung-Hwan Han c , Swapnil B. Ambade d , Oh-Shim Joo a,∗ a Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 130650, Republic of Korea b School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded, India c Inorganic Nanomaterials Laboratory, Hanyang University, 133-791 Seoul, Republic of Korea d Organic Optoelectronic Materials Laboratory, Division of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju, South Korea a r t i c l e i n f o Article history: Received 16 January 2012 Received in revised form 2 April 2012 Accepted 13 April 2012 Keywords: PANI nanorice Wet-chemical method Crystalline structure Supercapacitor a b s t r a c t One pot run mass-production of polyaniline (PANI) nanorice is carried out using a simple room temper- ature ingenious low temperature wet-chemical method. Different bondings are identified using Fourier transform infrared spectroscopy analysis. Crystalline structure, due to presence of well-defined rings in selected area electron diffraction pattern, and nanorice morphology, from the scanning electorn miscropy photoimages, of as-prepared PANI are confirmed. Using high-resolution trasmission elec- tron microscopy digital photoimage 0.46 nm and 0.37 nm fringe widths are monitored. Surface area of 41.06 m 2 g -1 is justified from the adsorption–desorption isotherms. The PANI nanorice electrode reveals 17.33 W h kg -1 energy density and the 480 W kg -1 power density due to significant inner charge contri- bution (68.28 C g -1 ) compared to outer charge. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Supercapacitors, commonly known as electrochemical capac- itors, store energy through reversible ion adsorption to facilitate specific high surface area onto active materials. Supercapaci- tors offer high power density, high charge storage and long life cycle [1,2]. Supercapacitors are expected to bridge the gap between batteries and capacitors owing to their high power density, high cycling life albeit with low energy density. The growing interest in these devices, in particular, in industrial research laboratories, is stimulated by their potential applica- tions in high power equipment and machines such as electric vehicles, high-energy pulsed lasers, camcorders, cellular phones, microelectronics, rechargeable batteries, electrochromic devices, etc. [3–7]. Electrical double layer capacitors (EDLCs) that generally introduce electrical charge at the electrode/electrolyte inter- face as described by the Gouy–Chapman–Stern–Grahame model and pseudocapacitors, arising from the fast reversible faradic redox reaction taking place on or near the surface of electrode utilize a redox reaction at the interface at certain potentials, are basically two main types of supercapacitors. Physicochemi- cal changes arise in both capacitors at the electrode/electrolyte ∗ Corresponding author. E-mail address: joocat@kist.re.kr (O.-S. Joo). interface. Hence, achieving high power and high energy den- sities is crucial for appreciable surface properties of material. Typically, high surface area carbon-based materials are widely studied for EDLCs [8–10]. On the other hand, conjugated poly- mers and metal oxides are well-known pseudocapacitors [11] that exhibit a high specific capacitance (SC) due to the redox activity via proton adsorption in an acidic electrolyte. To gener- ate high SC, the specific surface area of the electrode material needs to be as high as possible. Amongst the numerous mate- rials studied to date, various nanoforms of ruthenium oxide are clearly remarkable, demonstrated better quality electrochemical response [12]. Unfortunately, the use of an expensive ruthenium metal is reistricted in the commercialization process. Physical and chemical methods, used till date to synthesize polyaniline (PANI) nanostructures, include self-assembly, emulsion, template synthesis, electrodeposition and interfacial polymerization etc., wherein, these methods suffer mass-production advantage and are complicated to attach nanoscale-PANI, require large surfactant, and tedious to recycle after polymerization [13–20]. All methods produce limited quantity of PANI nanostructures i.e. few micro- grams to milligrams. Therefore, there is need to develop a novel low temperature chemical method that can be used for mass- production of PANI. Wet chemical method is presently attracting considerable attention as it is relatively inexpensive and simple and does not require sophisticated instrumentation like vacuum systems and other expensive equipments. A large quantity of 0379-6779/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.synthmet.2012.04.013