scholarly journals Insights into Enhanced Capacitive Behavior of Carbon Cathode for Lithium Ion Capacitors: The Coupling of Pore Size and Graphitization Engineering

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Kangyu Zou ◽  
Peng Cai ◽  
Baowei Wang ◽  
Cheng Liu ◽  
Jiayang Li ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Experimental Result ◽  
Carbon Cathode ◽  
Capacitive Behavior

AbstractThe lack of methods to modulate intrinsic textures of carbon cathode has seriously hindered the revelation of in-depth relationship between inherent natures and capacitive behaviors, limiting the advancement of lithium ion capacitors (LICs). Here, an orientated-designed pore size distribution (range from 0.5 to 200 nm) and graphitization engineering strategy of carbon materials through regulating molar ratios of Zn/Co ions has been proposed, which provides an effective platform to deeply evaluate the capacitive behaviors of carbon cathode. Significantly, after the systematical analysis cooperating with experimental result and density functional theory calculation, it is uncovered that the size of solvated PF6− ion is about 1.5 nm. Moreover, the capacitive behaviors of carbon cathode could be enhanced attributed to the controlled pore size of 1.5–3 nm. Triggered with synergistic effect of graphitization and appropriate pore size distribution, optimized carbon cathode (Zn90Co10-APC) displays excellent capacitive performances with a reversible specific capacity of ~ 50 mAh g−1 at a current density of 5 A g−1. Furthermore, the assembly pre-lithiated graphite (PLG)//Zn90Co10-APC LIC could deliver a large energy density of 108 Wh kg−1 and a high power density of 150,000 W kg−1 as well as excellent long-term ability with 10,000 cycles. This elaborate work might shed light on the intensive understanding of the improved capacitive behavior in LiPF6 electrolyte and provide a feasible principle for elaborate fabrication of carbon cathodes for LIC systems.

scholarly journals Design of Porous Carbons for Supercapacitor Applications for Different Organic Solvent-Electrolytes

2021 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Joshua Bates ◽  
Foivos Markoulidis ◽  
Constantina Lekakou ◽  
Giuliano M. Laudone
Keyword(s):  
Activated Carbon ◽  
Ion Transport ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Porous Electrode ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Specific Area ◽  
Porous Electrodes

The challenge of optimizing the pore size distribution of porous electrodes for different electrolytes is encountered in supercapacitors, lithium-ion capacitors and hybridized battery-supercapacitor devices. A volume-averaged continuum model of ion transport, taking into account the pore size distribution, is employed for the design of porous electrodes for electrochemical double-layer capacitors (EDLCs) in this study. After validation against experimental data, computer simulations investigate two types of porous electrodes, an activated carbon coating and an activated carbon fabric, and three electrolytes: 1.5 M TEABF4 in acetonitrile (AN), 1.5 M TEABF4 in propylene carbonate (PC), and 1 M LiPF6 in ethylene carbonate:ethyl methyl carbonate (EC:EMC) 1:1 v/v. The design exercise concluded that it is important that the porous electrode has a large specific area in terms of micropores larger than the largest desolvated ion, to achieve high specific capacity, and a good proportion of mesopores larger than the largest solvated ion to ensure fast ion transport and accessibility of the micropores.

Facile simulation of carbon with wide pore size distribution for electric double-layer capacitance based on Helmholtz models

2015 ◽  
Vol 3 (32) ◽  
pp. 16535-16543 ◽  
Author(s):  
Wei Hsieh ◽  
Tzyy-Leng Allen Horng ◽  
Hsin-Chieh Huang ◽  
Hsisheng Teng
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Double Layer ◽  
Density Functional ◽  
Local Density ◽  
Double Layer Capacitance ◽  
Local Density Functional Theory ◽  
Non Local ◽  
Forms Of Carbon

Incorporation of surface-based capacitances (C/S) simulated by Helmholtz models with pore size distribution obtained from the non-local density functional theory precisely predicts the double-layer capacitance of distinct forms of carbon.

scholarly journals Graphene Oxide: Study of Pore Size Distribution and Surface Chemistry Using Immersion Calorimetry

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1492
Author(s):  
Carlos A. Guerrero-Fajardo ◽  
Liliana Giraldo ◽  
Juan Carlos Moreno-Piraján
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Density Functional ◽  
Local Density ◽  
Donor Number ◽  
Immersion Enthalpy ◽  
Functional Theory

In this work, the textural parameters of graphene oxide (GO) and graphite (Gr) samples were determined. The non-local density functional theory (NLDFT) and quenched solid density functional theory (QSDFT) kernels were used to evaluate the pore size distribution (PSD) by modeling the pores as slit, cylinder and slit-cylinder. The PSD results were compared with the immersion enthalpies obtained using molecules with different kinetic diameter (between 0.272 nm and 1.50 nm). Determination of immersion enthalpy showed to track PSD for GO and graphite (Gr), which was used as a comparison solid. Additionally, the functional groups of Gr and GO were determined by the Boehm method. Donor number (DN) Gutmann was used as criteria to establish the relationship between the immersion enthalpy and the parameter of the probe molecules. It was found that according to the Gutmann DN the immersion enthalpy presented different values that were a function of the chemical groups of the materials. Finally, the experimental and modeling results were critically discussed.

scholarly journals Multimodels computation for adsorption capacity of activated carbon

2017 ◽  
Vol 36 (1-2) ◽  
pp. 508-520 ◽  
Author(s):  
Guodong Wang ◽  
Yun Tian ◽  
Jianchun Jiang ◽  
Jianzhong Wu
Keyword(s):  
Density Functional Theory ◽  
Activated Carbon ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Density Functional ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Functional Theory

The pore size distribution of activated carbon is conventionally characterized with nitrogen adsorption measurements at 77 K. The adsorption isotherms are commonly analyzed with a nonlocal density functional theory in combination with a mathematical model for the pore size and geometry. While nonlocal density functional theory is significantly more accurate than the Brunauer–Emmett–Teller theory for gas adsorption, its application to materials characterization is mostly based on a mean-field approximation for van der Waals attractions that is only qualitative in comparison with alternative versions of nonlocal density functional theory or molecular simulations. Toward development of a more reliable theoretical procedure, we compare mean-field approximation-nonlocal density functional theory with three recent versions of non-mean-field methods for gas adsorption at conditions corresponding to experiments for porous materials characterization. The potential applicability of different nonlocal density functional theory methods for pore size distribution predictions is evaluated in terms of the theoretical error bound scale analysis. We find that the weight density approximation is the most reliable for predicting the pore size distribution of amorphous porous materials. In addition to accurate isotherm, weight density approximation yields the theoretical error bound scale for pore size distribution prediction nearly 104 times narrower than that corresponding to mean-field approximation. The new theoretical procedure has been used to analyze the pore size distribution of four activated carbon samples and to predict the adsorption capacities of these materials.

Sign in / Sign up

Export Citation Format

Share Document