Zinc–Carbon Battery Recycling for Investigating Carbon Materials for Supercapacitor Applications

Abstract

In this paper, carbon materials, including graphene nanosheets and carbon nanoparticles, were prepared from spent zinc–carbon batteries by the following two simple methods: electrochemical exfoliation and ultrasonication. Here, graphene nanosheets were synthesized by electrochemical exfoliation in 0.5 M H2SO4 by using a direct current power supply with two carbon rods from spent zinc–carbon batteries. Carbon nanoparticles were prepared by fast ultrasonication in a low-cost, green solution of DI water and ethanol. Graphene nanosheets in this study have high quality, large scale, and good electrochemical ability, while carbon nanoparticles have a unique nanosize and a good specific surface area. These carbon materials were applied for electrochemical measurements for supercapacitor studies and showed excellent stability at different temperatures. Moreover, electric double-layer capacitor devices based on graphene nanosheets and carbon nanoparticles were also used in electrochemical studies with strong stability and good electrochemical capability.

Friendly Environmental Strategies to Recycle Zinc–Carbon Batteries for Excellent Gel Polymer Electrolyte (PVA-ZnSO4-H2SO4) and Carbon Materials for Symmetrical Solid-State Supercapacitors

“…The electrochemical studies of the supercapacitors were studied on an electrochemical workstation CS310 (Corrtest, China) by following various techniques including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD). Here, the specific capacitance of the supercapacitor ( C CV , F g –1 ) was calculated from CV, using the following equations: , C normalC normalV = ∫ I .25em normald V 2 × ( V 2 − V 1 ) × m × v where I (A) is the applied current, Δ V = ( V 2 – V 1 ) (V) is the working voltage window, m (g) is the total mass volume of electrode material, and v is the scan rate (V s –1 ).…”

“…Moreover, the specific capacitance of the three-electrode system ( C GCD , F g –1 ) and the symmetrical solid-state super capacitor (SSC) device ( C s , F g –1 ) were calculated from the charge–discharge curve, using the following equations: , C GCD = I × normalΔ t normalΔ V × m C s = 4 C GCD …”

“…The energy density ( E , W h kg –1 ) and power density ( P , W kg –1 ) were calculated by the following equations: , E = C normali × false( normalΔ V false) 2 2 × 1000 3600 P = E × 3600 normalΔ t where C i is the capacitance of working electrode in the three-electrode system ( C GCD ) or specific capacitance of devices ( C s ) and Δ t (s) is the discharge time.…”

“…Carbon nanoparticles were prepared by one simple step of washing before drying and grinding to obtain the final product ( Figure 1 ), following our previous report. 11 First, 2 g of carbon waste from spent zinc–carbon batteries was collected and transferred into 200 mL of ethanol with ultrasonics for 6 h to clean the remaining binder remaining. Second, this mixture was filtrated, washed several times with DI water, and dried in a vacuum oven at 80 °C for 48 h to obtain carbon powder.…”