ELECTROCHEMICAL CHARACTERISTICS OF MECHANOCHEMICALLY PREPARED POLYANILINE AND GRAPHENE BASED NANOCOMPOSITES AS ELECTRODES OF SUPERCAPACITORS

Abstract

To study the possibility of using of mechanochemically synthesized nanocomposites based on polyaniline and graphene as electrode materials for symmetric supercapacitors. Methods  of  cyclic voltammetry,  chronopotentiometry  and  impedance  spectroscopy were used for the SSC research. The charge-discharge cycling was performed at a working voltage of 0.65, 1.0 and 1.2 V. The discharge of SSC through a resistor was performed with the sequential switching of a charged SSC in an electrical circuit with a resistance of 10, 25, 50, 75 or 100 ohms. It has been established that the mechanochemically prepared nanocomposite PAni/nG can be  used  to  create  SSCs  that  are  able  to  maintain  stability  during  cycling  for  at  least  10,000  cycles  and provide a specific capacity ~ 360 F/g. The optimal operating voltage of the SSCs based on PAni/nG is 0.65
V. Increasing the voltage to 1.0 and 1.2 V leads to loss of stability of the SSCs as a result of degradation of the cathode. It has been found that the presence of nG nanoparticles in the volume of PAni causes a high stability of the SSC during long-term cycling, while similar devices based on ch-PAni do not possess this property. It has been shown that SSCs based on PAni/nG exhibit high speed characteristics and can function at high current loads at 30 A/g and provide a capacity of ~320 F/g. The specific power of such PAni/nG based SSCs can reach ~10 kW/kg with the specific energy value ~18 W/h/kg. Originality.  It  has  been  shown  that  the  mechanochemical  method  can  be  used  to  prepare
nanocomposites based on 2D-materials and graphene. Using a complex of various complementary research methods, it has been shown that the increase in specific capacity and improvement in cycling stability for the studied hybrid nanocomposites is caused not only by the presence in their structure of graphene particles,
but  also  by  the  mechanochemical  method  of  preparing  nanocomposites.  It  promotes  the  formation  of  a hybrid material structure that prevents degradation of a polymer at charge-discharge in an acidic medium. Practical value. The results of the work can be used to construct symmetric supercapacitors based on PAni/nG nanocomposites.