Facile Synthesis and High Anode Performance of Carbon Fiber-Interwoven Amorphous Nano-SiO_<i>x</i>/Graphene for Rechargeable Lithium Batteries

Nguyen, Dan Thien,Nguyen, Cao Cuong,Kim, Jong-Seon,Kim, Je Young,Song, Seung-Wan American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.21

<P>We present the first report on carbon fiber-interwoven amorphous nano-SiO<SUB><I>x</I></SUB>/graphene prepared by a simple and facile room temperature synthesis of amorphous SiO<SUB><I>x</I></SUB> nanoparticles using silica, followed by their homogeneous dispersion with graphene nanosheets and carbon fibers in room temperature aqueous solution. Transmission and scanning electron microscopic imaging reveal that amorphous SiO<SUB><I>x</I></SUB> primary nanoparticles are 20–30 nm in diameter and carbon fibers are interwoven throughout the secondary particles of 200–300 nm, connecting SiO<SUB><I>x</I></SUB> nanoparticles and graphene nanosheets. Carbon fiber-interwoven nano-SiO<SUB>0.37</SUB>/graphene electrode exhibits impressive cycling performance and rate-capability up to 5C when evaluated as a rechargeable lithium battery anode, delivering discharge capacities of 1579–1263 mAhg<SUP>–1</SUP> at the C/5 rate with capacity retention of 80% and Coulombic efficiencies of 99% over 50 cycles, and nearly sustained microstructure. The cycling performance is attributed to synergetic effects of amorphous nano-SiO<SUB><I>x</I></SUB>, strain-tolerant robust microstructure with maintained particle connectivity and enhanced electrical conductivity.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-21/am4034763/production/images/medium/am-2013-034763_0010.gif'></P>

Magnesium stannide as a high-capacity anode for magnesium-ion batteries

Nguyen, Dan-Thien,Song, Seung-Wan Elsevier 2017 Journal of Power Sources Vol.368 No.-

<P><B>Abstract</B></P> <P>Driven by the limited global resources of lithium, magnesium metal batteries are considered as potential energy storage systems. The battery chemistry of magnesium metal anode, however, limits the selection of electrolytes, cathode materials and working temperature, making the realization of magnesium metal batteries complicated. Herein, we report the development of a new magnesium-insertion anode, magnesium stannide (Mg<SUB>2</SUB>Sn), and demonstrate reversible electrochemical Mg<SUP>2+</SUP>-extraction and insertion of Mg<SUB>2</SUB>Sn anode at 0.2 V <I>versus</I> Mg, delivering discharge capacity of 270 mAhg<SUP>−1</SUP> in a half-cell with the electrolyte of PhMgCl/THF and enabling of room temperature magnesium-ion batteries with Mg<SUB>2</SUB>Sn anode combined with Mg-free oxide cathode and conventional-type electrolyte of Mg(TFSI)<SUB>2</SUB>/diglyme. The combination of Mg<SUB>2</SUB>Sn anode with various cathodes and electrolytes holds great promise for enabling room temperature magnesium-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mg<SUB>2</SUB>Sn, a high-capacity anode material showing Mg<SUP>2+</SUP>-insertion and extraction at 0.2 V. </LI> <LI> Synthesis of microsized bulk Mg<SUB>2</SUB>Sn anode material using a simple ball-milling. </LI> <LI> Stable cycling performance of coin half-cell, delivering discharge capacity 270 mAhg<SUP>-1</SUP>. </LI> <LI> Studies of interfacial reaction behavior of half-cell Mg<SUB>2</SUB>Sn anode by XPS analysis. </LI> <LI> Initial cyclability of RT Mg-ion battery, Mg<SUB>2</SUB>Sn//V<SUB>2</SUB>O<SUB>5</SUB>, in conventional electrolyte. </LI> </UL> </P>

Tin-based Alloy Anodes for Magnesium-ion Batteries

Dan-Thien Nguyen(누엔 단티엔),Seung-Wan Song(송승완) 한국신재생에너지학회 2017 한국신재생에너지학회 학술대회논문집 Vol.2017 No.9

Factors Affecting Mobile Payment Acceptance and Intention: A Case Study of Hospitality Customers in Vietnam

Dinh Tram Anh PHAN,Thi Thuy Ngan NGUYEN,Thi Khanh Nhi NGUYEN,Tran Thien An NGUYEN,Van Si Dan PHAN,Ngoc Phuong Thao HO,Kim Xuan DO,Trong Luan NGUYEN 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.5

The outbreak of the COVID-19 pandemic has had a significant impact on the Vietnamese economy. In the midst of a complex disease that compelled people to limit their interaction, customers’ shopping habits shifted from “offline” to “online” transactions. Mobile payments have also grown in popularity. The goal of this study is to figure out what factors influence the use of mobile payments by hotel clients in Can Tho after COVID-19. The research team also examines how those factors influence customers’ willingness to use mobile payment and makes recommendations to better the current situation. Primary data was collected from 227 persons using online surveys and processed with SPSS software for this study. To analyze the correlation relationship between the elements determining the intention to use, the Cronbach alpha, EFA, Correlation, and Regression methods used to assess the scale are applied. Perceived Trustworthiness, Perceived Usefulness, and Perceived Ease of Use all have positive effects on customers’ propensity to use, according to the findings. Perceived Security, on the other hand, has no bearing. The findings of this study have significant theoretical and practical implications for the development of mobile payment services in Can Tho, particularly following the implementation of COVID-19.

2P-388 Understanding the Electrochemical Behavior of Tin-based Alloy Anode Materials for Magnesium Ion Batteries

( Nguyen Thi Huong Giang ),( Nguyen Dan Thien ),송승완 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Rechargeable magnesium battery is a potential candidate as an alternative to lithium-ion battery for use in energy storage systems due to low cost, high specific volumetric capacity (3833 mAh/㎤) and reasonable gravimetric capacity (2205 mAh/g). However, the development of Mg cells still faces many challenges. The formation of electrochemically inactive surface blocking layer on Mg metal anode prohibits its reversible reaction in electrolyte containing commercially available magnesium salts such as Mg(TFSI)₂ or Mg(ClO₄)₂ in room temperature polar aprotic solvents. To mitigate those issues, insertiontype anode materials have been introduced as alternatives to Mg metal. Our recent works have demonstrated that tin-based materials have a high potential for use as anode active materials in Mg-ion batteries at room temperature. In this presentation, we will report the synthesis and characterization tin-alloy materials, and their electrochemical behavior in room temperature Mg-ion cells.

Improved Cycling Ability of Silicon-Graphite Composite Anode Materials through the SEI Control

김재람,조현탁,( Nguyen Dan Thien ),강길구,전도만,양아름,송승완 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Silicon-graphite composites has been considered as promising anode materials for higher energy density Li-ion batteries because of larger theoretical specific capacity of silicon than currently commercialized graphite. They, however, suffer from a large volume change during lithiation and delithiation, resulting in the particle cracking, an instability of the solid electrolyte interphase (SEI) and finally leading to poor cycle life. In order to solve the problems, several strategies in the aspects of improved electrical conductivity and buffering effect of volume change have been developed, which are the fabrication of silicon composites with carbon materials and the use of functional binder and electrolyte additives. Here, we focus on the control of electrode-electrolyte interfacial reaction and the formation of a stable SEI layer using various additives. The influence of SEI stability on cycling performance of silicon-graphite composite anodes would be discussed in the meeting.

Mechanism for the Stable Performance of Sulfur-Copolymer Cathode in Lithium-Sulfur Battery Studied by Solid-State NMR Spectroscopy

Hoefling, Alexander,Nguyen, Dan Thien,Partovi-Azar, Pouya,Sebastiani, Daniel,Theato, Patrick,Song, Seung-Wan,Lee, Young Joo American Chemical Society 2018 Chemistry of materials Vol.30 No.9

<P>Rechargeable lithium-sulfur (Li-S) batteries have drawn significant attention as next-generation energy storage systems. Sulfur-copolymers are promising alternative cathode materials to elemental sulfur in Li-S batteries as they provide high reversible capacity. However, the redox mechanisms of these materials are not well understood owing to the difficulty in characterizing amorphous structures and identifying individual ionic species. Here, we use solid-state NMR techniques together with electrochemistry experiments and quantum calculations to investigate the structural evolution of the prototype S-copolymer cathodes, sulfur-diisopropenylbenzene copolymers (poly(S-co-DIB)), during cycling. We demonstrate that polysulfides with different chain lengths can be distinguished by <SUP>13</SUP>C and <SUP>7</SUP>Li NMR spectroscopy, revealing that the structure of the copolymers can be tuned in terms of polysulfide chain lengths and resulting reaction pathways during electrochemical cycling. Our results show that the improved cyclability of these cathodes originates from the role of organic moieties acting as anchors that fixate polysulfides to the polymeric network during cycling, thus preventing their diffusion into the electrolyte. We provide a new methodological concept for the mechanistic studies to track the intermediate species and phase transition in Li-S batteries.</P> [FIG OMISSION]</BR>

Stabilizing the Solid Electrolyte Interphase Layer and Cycling Performance of SiliconGraphite Battery Anode by Using a Binary Additive of Fluorinated Carbonates

Jo, Hyuntak,Kim, Jaeram,Nguyen, Dan-Thien,Kang, Kil Ku,Jeon, Do-Man,Yang, A-Reum,Song, Seung-Wan American Chemical Society 2016 The Journal of Physical Chemistry Part C Vol.120 No.39

<P>Stabilization of the solid electrolyte interphase (SEI) layer of the silicon (Si) graphite composite anode for Li-ion batteries leads to an improvement of cycling performance. The SEI stabilization is achieved by utilizing a binary additive of fluoroethylene carbonate (FEC) and a fluorinated linear carbonate, di(2,2,2-trifluoroethyl)carbonate (DFDEC). The SEI composition analyses using attenuated total reflectance Fourier transform infrared (ATR FTIR) and X-ray photoelectron spectroscopy reveal that FEC alone plays a role in producing relatively more and various organic compounds including anhydride but lower concentration of inorganic salts, lowering interfacial resistances than those of conventional electrolyte and other additives. The SEI composition of silicon-graphite composite anode with FEC additive is distinguished from those reported for Si only and graphite only. The role of DFDEC alone, which possessed six fluorine atoms, is found to be the production of plenty of inorganic compounds such as Li2CO3, LiF, and OPF3-y(OR)(y)/LixPFyOz compounds, thickening the SEI layer. Blending of FEC and DFDEC results in the SEI thickening with the formation of mixtures of organic and inorganic compounds, which permits effective surface passivation of the anode, SEI robustness, and structural robustness of the silicon-graphite anode material. The anode with the binary additive of 10 wt % FEC and 1 wt % DFDEC outperforms the one in the conventional electrolyte and with FEC alone, delivering improved initial Coulombic efficiency of 84%, high discharge capacity of 742-601 mAh g(-1) of a whole active material, and 81% capacity retention at the 50th cycle.</P>