scholarly journals Investigation on Fabrication of Reduced Graphene Oxide-Sulfur Composite Cathodes for Li-S Battery via Hydrothermal and Thermal Reduction Methods

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 861
Author(s):  
Zhiqi Li ◽  
Hao Sun ◽  
Yuepeng Pang ◽  
Mingming Yu ◽  
Shiyou Zheng

Lithium-sulfur (Li-S) battery is considered one of the possible alternatives for next-generation high energy batteries. However, its practical applications are still facing great challenges because of poor electronic conductivity, large volume change, and polysulfides dissolution inducing “shuttle reaction” for the S cathode. Many strategies have been explored to alleviate the aforementioned concerns. The most common approach is to embed S into carbonaceous matrix for constructing C-S composite cathodes. Herein, we fabricate the C-S cathode reduced graphene oxide-S (rGO-S) composites via one step hydrothermal and in-situ thermal reduction methods. The structural features and electrochemical properties in Li-S cells of the two type rGO-S composites are studied systematically. The rGO-S composites prepared by one step hydrothermal method (rGO-S-HT) show relatively better comprehensive performance as compared with the ones by in-situ thermal reduction method (rGO-S-T). For instance, with a current density of 100 mA g−1, the rGO-S-HT composite cathodes possess an initial capacity of 1290 mAh g−1 and simultaneously exhibit stable cycling capability. In particular, as increasing the current density to 1.0 A g−1, the rGO-S-HT cathode retains a reversible capacity of 582 mAh g−1 even after 200 cycles. The enhanced electrochemical properties can be attributed to small S particles uniformly distributed on rGO sheets enabling to significantly improve the conductivity of S and effectively buffer large volume change during lithiation/delithiation.

Nanoscale ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 3808-3816
Author(s):  
Hongjin Xue ◽  
Yong Cheng ◽  
Qianqian Gu ◽  
Zhaomin Wang ◽  
Yabin Shen ◽  
...  

A close-knit CNTs coating that in-situ grown on the SiOx particles realizes the “soft-combination” between SiOx and CNTs, thus conquering the long-lasting issues of poor conductivity and large volume change of SiOx faced.


2020 ◽  
Vol 993 ◽  
pp. 646-653
Author(s):  
Shao Hui Liu ◽  
Yu Zhao ◽  
Xu Ran

In order to improve the interfacial bonding between graphene and copper and improve the dispersibility of graphene in the copper matrix, a novel method was used to prepare graphene. Firstly, graphene oxide (GO) was prepared by the modified Hummer's method, and then the reduced graphene oxide-supported cobalt nanoparticle composite powder (Co@RGO) was prepared by one-step in-situ reduction method. The fabricated materials were mixed with copper powder to obtain various volume fractions. The powder mixture was subjected to compression and discharge plasma sintering (SPS) to prepare a bulk copper-based composite material. The microstructure and its comprehensive properties were studied by SEM, TEM, XRD, FTIR and Raman. The results show that the agglomeration of graphene can be effectively inhibited after the cobalt nanoparticles supported on the graphene surface. The proper amount of Co@RGO could be uniformly dispersed in the copper matrix. The composite material showed a high electrical conductivity (>86% IACS), and the Vickers hardness also increased by about 30% compared with pure copper.


2016 ◽  
Vol 18 (16) ◽  
pp. 11157-11167 ◽  
Author(s):  
Sachin Kumar ◽  
Animesh K. Ojha ◽  
Donfack Patrice ◽  
Brajesh S. Yadav ◽  
Arnulf Materny

The rGO–CeO2nanocomposite exhibited excellent photocatalytic activity under sunlight irradiation.


2016 ◽  
Vol 18 (18) ◽  
pp. 13126-13127 ◽  
Author(s):  
Sachin Kumar ◽  
Animesh K. Ojha ◽  
Donfack Patrice ◽  
Brajesh S. Yadav ◽  
Arnulf Materny

Correction for ‘One step in situ synthesis of CeO2 nanoparticles grown on reduced graphene oxide as an excellent fluorescent and photocatalyst material under sunlight irradiation’ by Animesh Kumar Ojha et al., Phys. Chem. Chem. Phys., 2015, DOI: 10.1039/c5cp04457j.


2015 ◽  
Vol 815 ◽  
pp. 216-220 ◽  
Author(s):  
Muhammad Mahyiddin Ramli ◽  
K.N. Hanim ◽  
M.R. Muda ◽  
Siti Salwa Mat Isa ◽  
M.F. Jamlos

Large quantity of graphene oxide (GO) was prepared by Modified Hummer’s method, in which graphite was treated with a mixture of sulphuric acid, potassium permanganate and hydrogen peroxide. A chemically reduced graphene oxide (r-GO) was prepared using sodium borohydride (NaBH4), followed by thermal treatment and thermal treatment of chemically reduce using NaBH4. The electrical resistance of r-GO was measured using Keithley sourcemeter. The results revealed that r-GO show lower resistance on thermal reduction which is 2.39 kΩ compared to chemical reduction and thermal of NaBH4reduction which is 2.18 MΩ and 3.16 kΩ respectively. It can be concluded that thermal reduction is the best method to produce high conductivity r-GO film.


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