Electron Microscopy Investigation of Rice Husk-Derived Silicon-Tin/Nitrogen-Doped Graphene Composites Nanostructure

2020 ◽  
Vol 302 ◽  
pp. 51-61 ◽  
Author(s):  
Viratchara Laokawee ◽  
Thanapat Autthawong ◽  
Bralee Chayasombat ◽  
Aishui Yu ◽  
Thapanee Sarakonsri

Nowadays, there is an increasing of the demanding in high energy density lithium-ion batteries (LIBs) due to the growing of energy storage needs for electronic vehicles and portable devices. Silicon (Si) and Tin (Sn) are the promising anode materials for LIBs due to their high theoretical capacity of 4200 mAh/g and 994 mAh/g. Moreover, Si can be derived from rice husk which is the main agricultural product in Thailand. However, the using of Si and Sn encounters with the huge volume expansion during lithiation and delithiation process. To alleviate this problem, Nitrogen-doped graphene (NrGO), carbon supporter, is used as composite with these metals to buffer the volume change and increase the electrical conductivity of composites. This work aims to synthesis Si/NrGO and SiSn/NrGO nanocomposites and Si used in these composites is derived from rice husk. All products were characterized by X-rays diffraction (XRD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. XRD results showed that the composites contained phases of Si, Sn and carbon. The electron microscopy techniques were the main part to clarify the morphology and distribution of Si and Sn particles on NrGO. SEM and TEM results confirm that there were small sized particles of Si and Sn dispersed and covered on NrGO surface. Furthermore, the electrochemical properties of prepared composites were measured to confirm their efficiency as anode materials in lithium-ion batteries by coin cell assembly. The composite with 10 percent Si and 10 percent Sn on NrGO could deliver a high capacity around 480 mAh/g over 100 cycles and expected to use as anode materials in the next generation lithium-ion batteries.

2019 ◽  
Vol 7 (34) ◽  
pp. 19909-19921 ◽  
Author(s):  
Ronghua Wang ◽  
Qiannan Zhao ◽  
Weikang Zheng ◽  
Zongling Ren ◽  
Xiaolin Hu ◽  
...  

A 4.5 V “dual carbon” LIC device is constructed based on all nitrogen doped graphene nanostructures. It could achieve an ultrahigh energy density of 187.9 W h kg−1 at a high power density of 2250 W kg−1 due to the alleviating kinetic mismatch.


2021 ◽  
pp. 2150105
Author(s):  
NARUEPHON MAHAMAI ◽  
THANAPHAT AUTTHAWONG ◽  
AISHUI YU ◽  
THAPANEE SARAKONSRI

Lithium-ion batteries (LIBs) have become commercialized technologies for the modern and future world, but commercial batteries using graphite still have a low specific capacity and are concerned with safety issues. Silicon (Si) and antimony (Sb) nanocomposites have the tendency to be synthesized as high-energy-density anode materials which can be a solution for the above-mentioned problems. This work reported the synthesis methods and characterization of Sb and Si composited with nitrogen-doped graphene (SbSi/NrGO) by facile chemical method and thermal treatment. Si was obtained by magnesiothermic reduction of SiO2 derived from rice husk, waste from the agricultural process. To study the phases, particle distributions, and morphologies, all prepared composites were characterized. In this experiment, the phase compositions were confirmed as [Formula: see text]-Si, [Formula: see text]-Si, SiC, Sb, and shifted peaks of expanded C which were caused by NrGO synthesis. Interestingly, a good distribution of Si and Sb particles on the NrGO surface was obtained in 15Sb15Si/NrGO composition. It could be due to appropriate Sb and Si contents on the NrGO surface area in composite materials. Morphological identification of synthesized products represented the Sb and Si particles in nanoscale dispersed on thin wrinkled-paper NrGO. These results suggested that the synthesis method in this paper is appropriate to prepare SbSi/NrGO nanocomposites to be used as high-performance anode materials in high-performance LIBs for advanced applications.


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