All Graphene Lithium Ion Capacitor with High-Energy-Power Density Performance

Abstract

Taking advantage of the extended specific surface area and high conductivity, graphene has been widely subjected to extensive investigations by many research groups. Herein, three-dimensional graphene (3DG) were prepared by a facile and scalable ion-exchange method, which exhibited a porous structure with a specific surface area of 2400 m 2 /g and pore volume of 2.0 cm 3 /g. In a typical synthesis, two key procedures played an important role in preparing the novel characteristics of 3DG: First, metal ions were used as the catalysis to graphitize the ion-exchange resin. Second, an KOH activation step at low temperatures (800 ℃) was applied on the exchange resin to produce a hierarchical porous structure of 3DG materials. The method of catalysis, chemical activation and heating treatment can form a unique interconnected structure and also effectively prevent graphene nanosheets from aggregating. Various structural and morphology analyses have been characterized by X-ray powder diffraction, Raman, Scanning electron microscope and Transmission electron microscope. Additionally, the enhanced specific surface area can improve capacitor performance of 3DG, which exhibited a high specific capacitance of 250 F/g when measured in a three-electrode system (KOH aqueous solution) and 120 F/g in a symmetric supercapacitor (TEMABF 4 /PC organic electrolytes). Furthermore, the as-prepared 3DG were successfully employed as both cathode and anode active materials for lithium ion capacitors (3DG-LIC) with high energy density (105 Wh/kg) because the potential window of 3DG-LIC extended from 2.5 to 4.0 V compared to traditional supercapacitor (SC) by prelithiation of anode. The performance and operating mechanism of 3DG-LIC were further studied by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The similar chemistry and microstructure maximizes the capacity and rate performance of cathode and anode, which indicates that the 3DG-LIC can be a promising candidate for high-energypower storage system and would have a wide application in other electrochemical applications.

Investigation of the Nanocrystal CoS2 Embedded in 3D Honeycomb-like Graphitic Carbon with a Synergistic Effect for High-Performance Lithium Sulfur Batteries

“…Synthesis and Characterization of the CoS 2 @ HPGC Hybrid Structure. The honeycomb-like HPGC adopted in this work is fabricated with a one-step metalcatalyzed/alkali-activation method developed in our previous work, 35 and the average particle size is about 26.90 μm, Figure S1. The HPGC possesses a unique honeycomb-like weight ratio of hierarchical porous structure, which is composed of a submicrometer-sized macroporous (300−500 nm pore size) network along with interconnected mesopores with a pore size of 30−100 nm, as shown in SEM in Figure 2a and TEM in Figure 2b; the uniform distribution of micropores and the graphitic layers (as indicated by arrows) can be clearly observed via HRTEM in Figure 2c.…”

Enhanced Electrochemical Performance by In Situ Phase Transition from SnS2 Nanoparticles to SnS Nanorods in N-Doped Hierarchical Porous Carbon as Anodes for Lithium-Ion Batteries

“…HPC was fabricated as per the previous paper. 31 Tin chloride dehydrate, ethylene glycol (EG), thiourea, polyacrylonitrile, and N,N-dimethylformamide were purchased from Sigma-Aldrich. The electrolyte of LiPF 6 (1 M) in ethylene carbonate/diethyl carbonate (EC/DEC: 3:7, vol %) used in this work was from Ningbo Shanshan Co., China.…”

“…HPC was fabricated as per the previous paper . Tin chloride dehydrate, ethylene glycol (EG), thiourea, polyacrylonitrile, and N , N -dimethylformamide were purchased from Sigma-Aldrich.…”

Promoting Reversible Redox Kinetics by Separator Architectures Based on CoS2/HPGC Interlayer as Efficient Polysulfide‐Trapping Shield for Li–S Batteries

“…Synthesis of CoS 2 /HPGC: HPGC was fabricated as shown in the previous publication. [28] CoS 2 nanoparticles embedded in HPGC (CoS 2 /HPGC) were synthesized by a solvothermal methodology. First, HPGC (100 mg) was dispersed in ethylene glycol (20 mL) by sonicating for 1 h. Cobalt acetate (50 mg) and thiourea (800 mg) were dissolved in deionized (DI) water, and then added into the prepared HPGC suspension.…”