(Invited) Advanced Energy Storages Based on Carbon Nanomaterials and 2D Materials
Authors: Choi Wonbong 
Published: February 2020

In this paper, I will present our team's recent advance in nanomaterials for high efficiency energy storages. Next-generation energy storage devices, such as Li-ion batteries (LIBs), supercapacitors and Li-sulfur batteries (LiS), demand high energy, power and better safety. Conventional graphite anode in Li-ion batteries falls short of fulfilling all these necessities. Carbon nanostructural materials (graphene and carbon nanotubes) have gained the spotlight as promising active materials for energy storage; they exhibit unique physico-chemical properties such as large surface area, short Li+ ion diffusion length, and high electrical conductivity, in addition to their long-term stability. Among all published literatures in Li-ion battery, nanostructured carbon materials occupy ~ 70%. Such an impressive figure signifies high interest and promising future of this class of materials in energy storage devices and compels us to look into the involved issues deeply. Carbon-nanostructured materials have issues with low areal and volumetric densities for the practical applications in electric vehicles, portable electronics, and power grid systems, which demand higher energy and power densities. One approach to overcoming these issues is to design and apply a three-dimensional (3D) electrode accommodating a larger loading amount of active materials (e.g., sulfur) while facilitating Li+ ion intercalation. Furthermore, 3D nanocarbon frameworks can impart a conducting pathway and structural buffer to high-capacity non-carbon nanomaterials, which results in enhanced Li+ ion storage capacity. Recent advance of two-dimensional (2D) materials enables us to design/fabricate atomic layer deposition on electrode materials for high-efficiency active electrode materials: (1) MoS2 - coated Li metal anode demonstrates a stable Li electrodeposition with the suppression of nucleation sites for dendrite growth. The MoS2 coated Li anodes assembled with 3D carbon nanotube-sulfur cathodes provide superior electrochemical performance ever reported to date. (2) 3D CNTs-MoS2 anode shows vertically-oriented MoS2 nanoflakes strongly bonded onto CNTs surface. The 3D CNTs-MoS2 shows high capacity, outstanding cycling stability, and good rate capability in Li-ion battery performance. The superior performance of 3D carbon nanotube structure and 2D materials in energy storages will be presented along with their mechanistic analysis.

References:

High performance rechargeable Li-S batteries using binder-free large sulfur-loaded three- dimensional carbon nanotubes, M Patel, E Cha, C Kang, B Gwalani, W Choi, Carbon http://dx.doi.org/10.1016/j.carbon.2017.03.035 (2017)

MoS2 as lithium protective layer for high performance lithium sulfur batteries, Cha, E., Patel, M.D., Park, J., Hwang, J., Prasad, V., Cho, K., and Choi, W.,
Nature Nanotechnology
, 2017.

(Invited Review) Three-Dimensional Carbon Nanostructures for Advanced Lithium-Ion Batteries, Chiwon Kang, Eunho Cha, Mumukshu D. Patel, H. Felix Wu, Wonbong Choi, Journal of Carbon Research C 2016, 2(4), 23; doi:10.3390/c2040023 (2016)

MoS2-reinforced 3D carbon nanotubes for next generation Li-ion batteries, Mumukshu D. Patel, Eunho Cha, Nitin Choudharya, Chiwon Kang, Wonki Lee, Jun Yeon Hwang, Wonbong Choi, Nanotechnology, 27 (2016) 495401

Recent development of 2D materials and their applications, W Choi, N Choudhary, J Park, D Akinwande, Y Lee, Materials Today, http://doi.org/10.1016/j.mattod.2016.10.002, (2016)

Three-dimensional free-standing carbon nanotubes for a flexible lithium-ion battery anode C Kang , E Cha , R Baskaran, W Choi, Nanotechnology 27 (2016) 105402

Directly deposited MoS2 thin film electrodes for high performance supercapacitors, N. Choudhary, M. Patel, Y Ho, N. Dahotre, J. Hwang, W. Choi, Materials Chemistry A (2015) DOI: 10.1039/C5TA08095A

Three-dimensional carbon nanotubes for high capacity lithium-ion batteries, C Kang, M Patel, B Rangasamy, K Jung, C Xia, S Shi, W Choi, Jr. Power Sources, 299 465-471 (2015)

Large Scale Patternable 3D Carbon Nanotubes-Graphene Structure for Flexible Li-ion Battery, C Kang, R Baskaran, J Hwang, B Ku, W Choi, Carbon 493-500 (2014)