Seawater zinc/polypyrrole-air cell possessing multifunctional charge-discharge characteristics

An environmentally friendly cell using polypyrrole-air regenerative cathode and zinc as anode is investigated in the 3% sodium chloride solution. The cell can operate in different charge and discharge mode. Polypyrrole can be reoxidized (doped) with chloride anions either by using dissolved oxygen or by an external power supply, e.g., small photovoltaic cell. In that way, after discharge, capacity retaining can be achieved by using seawater as the electrolyte. During low discharge rate, the delicate balance between solid state diffusion-controlled dedoping and chemical oxidation of polypyrrole produced by hydrogen peroxide is achieved, generating stable voltage plateau. The cell is proposed to operate as a power supply for different sensor devices in two modes. In the low discharge mode (10-20 mA g(-1)), it can be used for data acquisition, and at the fast discharge mode (up to 2 A g(-1)) for collecting data transmission

Synthesis of ternary polypyrrole/Ag nanoparticle/graphene nanocomposites for symmetric supercapacitor devices

In this study, novel ternary synthesis of reduced graphene oxide (rGO) sheets via intercalation of Ag nanoparticles (Ag) and polypyrrole (PPy) was obtained for supercapacitor evaluations. The synthesis procedure of nanocomposite is simple, cheap, and ecologically friendly. The nanocomposites were analyzed by Fourier transform infrared-attenuated transmission reflectance (FTIR-ATR) and scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX). In addition, electrochemical performances of electrode active materials (rGO/Ag/PPy) of the samples were tested by means of galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The highest specific capacitance and energy density of rGO/Ag/PPy nanocomposite were obtained as C-sp = 1085.22 F/g and E = 36.92 Wh/kg for [rGO](o)/[Py](o) = 1/5 at 4 mV/s in 1 M H2SO4 solution. Under the optimized preparation conditions in different initial feed ratios ([rGO](o)/[Py](o) = 1/1, A 1/2, 1/5, and 1/10) of rGO/Ag/PPy, nanocomposites acquired a high Coulombic efficiency, and a retention of 66% of its initial capacitance for [rGO](o)/[Py](o) = 1/10 after 1000 cycles. GCD and EIS measurements of rGO/Ag/PPy nanocomposite electrode active material allowed for supercapacitor applications.Namik Kemal University, Tekirdag, TurkeyNamik Kemal University [NKUBAP.01.GA. 16.076]The fact that this study was financed by Namik Kemal University, Tekirdag, Turkey, project number: NKUBAP.01.GA. 16.076 is gratefully acknowledged. Authors also thank Expert Muhammet Aydin (Namik Kemal Uni., NABILTEM, Tekirdag, Turkey) for recording SEM-EDX and FTIR-ATR measurements