Intensification of Pseudocapacitance by Nanopore Engineering on Waste-Bamboo-Derived Carbon as a Positive Electrode for Lithium-Ion Batteries.

Jong Chan Hyun,Jin Hwan Kwak,Seung-Soo Kim,Young Soo Yun,Jinsoo Kim,Jaewon Choi,Min Eui Lee

doi:10.3390/ma12172733

Abstract

Nanoporous carbon, including redox-active functional groups, can be a promising active electrode material (AEM) as a positive electrode for lithium-ion batteries owing to its high electrochemical performance originating from the host-free surface-driven charge storage process. This study examined the effects of the nanopore size on the pseudocapacitance of the nanoporous carbon materials using nanopore-engineered carbon-based AEMs (NE-C-AEMs). The pseudocapacitance of NE-C-AEMs was intensified, when the pore diameter was ≥2 nm in a voltage range of 1.0~4.8 V vs Li+/Li under the conventional carbonate-based electrolyte system, showing a high specific capacity of ~485 mA·h·g−1. In addition, the NE-C-AEMs exhibited high rate capabilities at current ranges from 0.2 to 4.0 A·g−1 as well as stable cycling behavior for more than 300 cycles. The high electrochemical performance of NE-C-AEMs was demonstrated by full-cell tests with a graphite nanosheet anode, where a high specific energy and power of ~345 Wh·kg−1 and ~6100 W·Kg−1, respectively, were achieved.

Highlights

Lithium-ion batteries (LIBs) are widely used power sources ranging from compact electronic devices to the grid system, and their applications are increasing rapidly with advances in modern technology, such as internet of things, wearable electronic devices, drones, and electric vehicles [1,2,3,4,5].The rapidly growing markets require higher energy/power densities and longer cycle lives, but the current LIB system has limited electrochemical performance [6,7]
Carbon-based active electrode materials (C-AEMs) composed of multiple polyhexagonal carbon (PHC) building blocks have an idiosyncratic nature arising from the sp2 -conjugated bonding structure and aromaticity [9,10,11,12]
The resulting products are called NE2-C-AEMs, NE4-C-AEMs, NE6-C-AEMs, and NE8-C-AEMs according to the weight ratio of the activation agent to the precursor

Summary

Introduction

Lithium-ion batteries (LIBs) are widely used power sources ranging from compact electronic devices to the grid system, and their applications are increasing rapidly with advances in modern technology, such as internet of things, wearable electronic devices, drones, and electric vehicles [1,2,3,4,5]. Carbon-based active electrode materials (C-AEMs) composed of multiple polyhexagonal carbon (PHC) building blocks have an idiosyncratic nature arising from the sp2 -conjugated bonding structure and aromaticity [9,10,11,12] They can readily donate or accept a delocalized electron with charge compensation caused by counter-ion adsorption on the surface of PHCs [13,14,15]. The relationship cannot be understood by simple linear behavior because all the active surfaces in the highly complex microstructure of C-AEMs could not be exposed to the charge carriers in the electrolyte This means that the redox-active heteroatoms can work under specific conditions with an effective active surface area (EASA) that is accessible to charge carriers. NE-C-AEMs demonstrated their competitive electrochemical performance in both half-cell and full-cell tests

Preparation of NE-C-AEMs

Characterization

Electrochemical Characterization

Results and Discussion

Electrochemical properties of the NE-C-AEMs

Conclusions