Preparation And Electrochemical Performance Of Conductive Polymer Composites Utilizing Spent Battery Powder

Supercapacitors have been extensively studied as energy-storage devices mainly due to their high energy density and power density, good cycle stability, fast chargedischarge rate and safe operation. Different materials were used as electrode materials of supercapacitor to improve the electrochemical performance of supercapacitor. Among these materials, polypyrrole(PPy) and polyaniline(PANI) in conducting polymers are important electrode materials; manganese dioxide(MnO2) is metal oxide with good performance; graphene can be used as the matrix and the template of other materials because of its unique structure and ultimately improves the electrochemical performance of composite materials.In recent years, the preparation of high yield functional materials utilizing spent dry batteries has become a research hotspot because large numbers of spent dry batteries are discarded in the environment which is harmful to the environment and human health. MnO2 and graphite powder(G) are the main components in the spent dry battery powder(SBP), thus the SBP might be used for preparing the conductive polymer-based composites which are applied in supercapacitors as the electrode materials.In this article, the energy storage principle of supercapacitor, electrode materials, polypyrrole, polyaniline and conductive polymer matrix composites, the recycling status and research progress of spent dry battery were summarized. The SBP as raw material, were used for the preparation of PPy and PANI composites. The influences of different reaction conditions on the morphology, yield, electrical conductivity, and electrochemical performances of products were investigated. Detailed experiment contents were included in the following three parts:(1) Binary G/PPy and ternary G/MnO2/PPy composites were prepared with pyrrole as monomers via in-situ chemical oxidative polymerization method under the oxidation of MnO2 in the SBP. The influences of various hydrochloric acid concentration, MnO2/pyrrole molar ratio, p-toluene sulfonic acid sodium/pyrrole(p-TSNa/pyrrole) molar ratio and acid solution volume on their morphology, yield, electrical conductivity, and electrochemical performances were investigated. The result showed that the performances of G/PPy composites were better than those of G/MnO2/PPy composites due to the lower capacity property of MnO2 with poor crystallinity in the SBP. When pTSNa/pyrrole mole ratio was 1.0, G/PPy composites had better electrochemical performances. Among them, G/PPy-11 composite had the highest specific capacitance of 212 F/g and retained 89.5% of its initial specific capacitance after 1000 cycles, indicating its good electrochemical stability.(2) Binary and ternary PANI-based composites were synthesized by mixing and stirring SBP and aniline monomers in ice bath under different reaction conditions, such as hydrochloric acid concentration, MnO2/aniline molar ratio and acid solution volume. The result showed that G/PANI composites prepared in 1.0 mol/L HCl had higher specific capacitance, and the performances of binary composites were better than those of ternary composites. Among them, G/PANI-14 composite had the highest specific capacitance of 317 F/g and retained 84.6% of its initial capacitance after 1000 cycles, indicating its good cyclic stability.(3) On the basis of optimum polymerization condition of polyaniline composites obtained in the second work, GO/G/PANI composites were prepared by adding graphene oxide(GO) to the reaction system of aniline and SBP. Under the reduction of hydrazine hydrate, GO/G/PANI composites could be turned into rGO/G/PANI composites(rGO is reduced graphene oxide). The effect of the amount of GO on the performances of the composites was investigated. The electrochemical test results showed that the addition of GO could improved the electrochemical performances of resulted GO/G/PANI composites compared to G/PANI composites. The electrochemical performances of rGO/G/PANI composites were further improved after the use of hydrazine hydrate. When the mass ratio of graphene/aniline was 1:10, rGO/G/PANI-3 had the best electrochemical properties with the highest specific capacitance of 421 F/g and retaining 106.6% of its initial capacitance after 1000 cycles. We synthesized supercapacitor electrode materials with high performance, and provided a new method for the reuse of spent dry batteries.