Nanoporous Titanium-Oxo Molecular Cluster for CO2 Selective Adsorption

Jun Byeongsun,Lee Chi Ho,Kim Joonwoo,Lee Sang Uck 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.7

Metal–organic frameworks (MOFs), a new family of porous materials, have received great attention over the past several decades as potential materials for gas separation and storage, and drug delivery. However, the widespread use of these materials has been seriously hampered by their susceptibility to moisture, which impacts their sorption properties. Here, we explored the sorption properties of a titanium-oxo cluster that can maintain sorption properties in a humid environment for CO2 capture and H2 purification using Monte Carlo (MC) simulations and density functional theory (DFT). The CO2, N2, CH4, and H2 gas-sorption properties of the titanium-oxo cluster were investigated using by comparing sorption site and binding energies, demonstrating that the titanium-oxo cluster can be utilized as a CO2 separator and H2 purification. The comparison between MC and DFT calculations reveals that atomistic MC simulation is particularly useful in the investigation of the sorption behavior of such a complex material.

Temperature-dependent lithium diffusion in phographene: Insights from molecular dynamics simulation

Siby Thomas,Saibal Jana,Byeongsun Jun,이치호,Sang Uck Lee 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

It is noteworthy to elucidate the underlying atomistic insights of next-generation battery electrodematerials to overcome the existing constraints associated with its rapid progress. By employing classicalmolecular dynamics (MD) simulations, we have studied the temperature dependent structural, thermomechanical,and Lithium diffusion properties of α- and β-phographene (PhoG) for Lithium-ion battery(LIB) anode applications. Our results show that at 300 K both the PhoGs possess negative thermalexpansion coefficient and is expounded as proof of anharmonicity present in it due to the existence ofpliable bending modes in the out-of-plane direction. The computed ultrahigh stiffness of PhoG helps toprevent the acute lattice expansion issue upon Li intercalation. The study also brings out that Li atomcould freely diffuse on the surface of the PhoGs, and thus a fast Li diffusivity and superior conductivity isobserved. The calculated Li diffusion activation energies (<0.20 eV) of these membranes are lower thanmany of the typical for Li-based graphitic anode with a Li diffusion coefficient of 10 10–10 12cm2 s 1. Inthis regard, the excellent structural and thermo-mechanical stability, and low activation energy barrier inPhoGs assures its application as an anode material in high-performance LIBs.

Quantitative Correlation between Carrier Mobility and Intermolecular Center-to-Center Distance in Organic Single Crystals

Park, Yoonkyung,Park, Kyung Sun,Jun, Byeongsun,Lee, Yong-Eun Koo,Lee, Sang Uck,Sung, Myung Mo American Chemical Society 2017 Chemistry of materials Vol.29 No.9

<P>Charge transport properties of organic semiconductors critically depend on their molecular packing structures. Controlling the charge transport by varying the molecular packing and understanding their structure property correlations are essential for developing high-performance organic electronic devices. Here, we demonstrate that the charge carrier mobility in organic single-crystal nanowires can be modulated with respect to the intermolecular center-to-center distance by applying uniaxial strain to the cofacially stacked crystals. Monotonic changes in charge carrier mobility (from 0.0196 to 19.6 cm(2)V(-1)s(-1) for 6,13-bis(triisopropylsilylethylnyl) pentacene (TIPS-PEN)) were observed under a wide range of strains from 16.7% (compressive) to 16.7% (tensile). Furthermore, the measured values of charge carrier mobility were in good agreement with theoretical calculations based on charge localized hopping theory. These results provide a definitive relationship between intermolecular packing arrangement and charge transports, which enables a huge improvement in charge carrier mobility for organic single-crystal materials.</P>

Two-dimensional haeckelite h567: A promising high capacity and fast Li diffusion anode material for lithium-ion batteries

Thomas, Siby,Jung, Hoejoong,Kim, Suyeon,Jun, Byeongsun,Lee, Chi Ho,Lee, Sang Uck Elsevier 2019 Carbon Vol.148 No.-

<P><B>Abstract</B></P> <P>There is great interest in finding suitable electrode materials for metal-ion batteries with good performance, low diffusion barriers and high capacity. Using the art of density functional theory (DFT), we systematically evaluated the possibility of planar carbon haeckelite structures (h567, r57, and o567) for a suitable anode in Lithium-ion batteries (LIBs). Our results show that haeckelites possess significant structural, mechanical, and electronic stability with high metallicity for LIB anode applications. Especially, the haeckelite h567 shows improved specific capacity (Li<SUB>1<I>.</I>875</SUB>C<SUB>6</SUB> ∼ 697 mAhg<SUP> <I>−</I>1</SUP>) compared to LiC<SUB>6</SUB> graphite due to the negative Li binding energy without clustering of Li atoms. In addition, it is worth noticing that the low open-circuit voltage (<0.30 V) and Li diffusion energy barrier (E<SUB> <I>a</I> </SUB> < 0.35 eV) of the haeckelite h567comparable to that of the graphite is beneficial to the overall performance of the LIBs. Based on the excellent electronic structure, superior Li mobility, extremely high in-plane stiffness, low open-circuit voltage, and high specific capacity, haeckelite h567 can be a promising anode material for the low-cost and high-performance LIBs.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

B3S monolayer: prediction of a high-performance anode material for lithium-ion batteries

Jana, Saibal,Thomas, Siby,Lee, Chi Ho,Jun, Byeongsun,Lee, Sang Uck Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.20

<P>To mitigate the ever-growing global temperature rise, renewable energy is needed and use of fossil fuels has to be reduced on an urgent basis. Next-generation renewable energy technology demands electrode materials with suitable structural, electronic, and mechanical properties. Through particle swarm-intelligence and first-principles structure calculations, we have designed a new novel B3S monolayer, which is dynamically, mechanically, and thermally stable and of higher cohesive energy compared to synthesized B2S3 thus ensuring the feasibility of experimental synthesis. As an anode material, the B3S monolayer can be expected to have high performance with high storage capacity (1662 mA h g<SUP>−1</SUP>), low open-circuit voltage (∼0.16 V) and a low lithium diffusion barrier (<I>E</I>a < 0.4 eV). Furthermore, the metallicity of the B3S monolayer is sustained after lithium adsorption, indicating good electrical conductivity and battery operating cycle. Our results clarify that these intriguing properties make B3S monolayer an appealing candidate for anode material in lithium-ion batteries.</P>

Phographene as a High-Performance Anode Material with High Specific Capacity and Fast Li Diffusion: From Structural, Electronic, and Mechanical Properties to LIB Applications

Thomas, Siby,Lee, Chi Ho,Jana, Saibal,Jun, Byeongsun,Lee, Sang Uck American Chemical Society 2019 The Journal of Physical Chemistry Part C Vol.123 No.35

<P>The progress of ecofriendly, clean, and sustainable energy resources always demands suitable anode materials for batteries with high structural stability and superior storage capacity. Herein, we use density functional theory predictions to examine the potential features of newly proposed planar membranes consist of 5-, 6- and 8- membered carbon rings, named as α- and β-phographene (PhoG). Our calculations disclose that both α- and β-PhoG structures possess high structural, thermal, and mechanical stability with intrinsic metallic characteristics. We have further extended our calculations of PhoG as a suitable anode material for use in Lithium-ion batteries. Our results reveal the Li adsorption in PhoG is exothermic and the α-PhoG show a higher theoretical specific capacity of Li<SUB>2.4</SUB>C<SUB>6</SUB> for Li atoms (892 mAh g<SUP>-1</SUP>) compared to the LiC<SUB>6</SUB> of graphite. We also found that both the α- and β-PhoG structures show fast Li mobility with a low diffusion barrier for Li atoms (<0.30 eV) as well as low average open circuit voltage (∼0.26 V). Our findings show that both the PhoG structures, especially α-PhoG, are suitable anode candidates for use in future Li-ion batteries owing to the metallic characteristic combined with the low open circuit voltage, low diffusion barrier, high Li storage capacity, and high thermo-mechanical stability. Our results would supply guidelines to develop better high-capacity anode materials for future Li-ion batteries.</P> [FIG OMISSION]</BR>