A comparative first-principles study of the lithiation, sodiation, and magnesiation of black phosphorus for Li-, Na-, and Mg-ion batteries

Hembram, K. P. S. S.,Jung, Hyun,Yeo, Byung Chul,Pai, Sung Jin,Lee, Heon Ju,Lee, Kwang-Ryeol,Han, Sang Soo The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.31

<P>Using first-principles calculations, we describe and compare atomistic lithiation, sodiation, and magnesiation processes in black phosphorous with a layered structure similar to graphite for Li-, Na-, and Mg-ion batteries because graphite is not considered to be an electrode material for Na- and Mg-ion batteries. The three processes are similar in that an intercalation mechanism occurs at low Li/Na/Mg concentrations, and then further insertion of Li/Na/Mg leads to a change from the intercalation mechanism to an alloying process. Li and Mg show a columnar intercalation mechanism and prefer to locate in different phosphorene layers, while Na shows a planar intercalation mechanism and preferentially localizes in the same layer. In addition, we compare the mechanical properties of black phosphorous during lithiation, sodiation, and magnesiation. Interestingly, lithiation and sodiation at high concentrations (Li2P and Na2P) lead to the softening of black phosphorous, whereas magnesiation shows a hardening phenomenon. In addition, the diffusion of Li/Na/Mg in black phosphorus during the intercalation process is an easy process along one-dimensional channels in black phosphorus with marginal energy barriers. The diffusion of Li has a lower energy barrier in black phosphorus than in graphite.</P>

Unraveling the Atomistic Sodiation Mechanism of Black Phosphorus for Sodium Ion Batteries by First-Principles Calculations

Hembram, K. P. S. S.,Jung, Hyun,Yeo, Byung Chul,Pai, Sung Jin,Kim, Seungchul,Lee, Kwang-Ryeol,Han, Sang Soo American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.27

<P>As opposed to the standard graphite anode used for lithium (Li) ion batteries (LIBs), a standard anode material for sodium (Na) ion batteries (NIBs) has not yet been reported. Black phosphorus is potentially very attractive as an anode material for NIBs, as it has a layered structure similar to graphite but a greater interlayer distance. In this work, we propose an atomistic mechanism for the sodiation of black phosphorus, based on first-principles calculations. The layered structure of black phosphorus is maintained up to the composition of Na<SUB>0.25</SUB>P, with <I>one-dimensional</I> sodiation (an intercalation process) occurring in the interlayer spaces of the black phosphorus, resulting in sliding of the phosphorene layers because one Na atom tends to bind to four P atoms. At Na levels beyond Na<SUB>0.25</SUB>P, the intercalation process changes to an alloying process. Sodiation exceeding the critical composition leads to breaking of P–P bonds and eventual formation of an amorphous phase from the layered Na<SUB><I>x</I></SUB>P structure. After the P–P bonds in the layered Na<SUB><I>x</I></SUB>P structure are broken, in a progress in which staggered P–P bonds are preferentially broken rather than planar P–P bonds, P<SUB>2</SUB> dumbbells are generated. As sodiation proceeds further, most of the P<SUB>2</SUB> dumbbells become isolated P atoms. Thus, in the amorphous Na<SUB>3</SUB>P phase, only low-coordinate P components such as isolated atoms (primarily) and dumbbells are found. We expect that our comprehensive understanding of the sodiation mechanism in black phosphorus will provide helpful guidelines in designing new types of black phosphorus anodes to obtain better performing NIBs.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-27/acs.jpcc.5b05482/production/images/medium/jp-2015-054822_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b05482'>ACS Electronic Supporting Info</A></P>

Tuning the Electronic and Magnetic Properties of Phosphorene by Vacancies and Adatoms

Srivastava, Pooja,Hembram, K. P. S. S.,Mizuseki, Hiroshi,Lee, Kwang-Ryeol,Han, Sang Soo,Kim, Seungchul American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.12

<P>We report a density functional theory (DFT) study regarding the effects of atomic defects, such as vacancies and adatom adsorption, on the electronic and magnetic properties of phosphorene (a two-dimensional monolayer of black phosphorus). A monovacancy in the phosphorene creates an in-gap state in the band gap of pristine phosphorene and induces a magnetic moment, even though pristine phosphorene is nonmagnetic. In contrast, both planar and staggered divacancies do not change the magnetic properties of phosphorene, although a staggered divacancy creates states in the gap. Our DFT calculations also show that adsorption of nonmetallic elements (C, N, and O) and transition metal elements (Fe, Co, and Ni) can change the magnetic properties of phosphorene with or without vacancies. For example, the nonmagnetic pristine phosphorene becomes magnetic after the adsorption of N, Fe, or Co adatoms, and the magnetic phosphorene with a monovacancy becomes nonmagnetic after the adsorption of C, N, or Co atoms. We also demonstrate that for O- or Fe-adsorbed monovacancy structure the electronic and magnetic properties are tunable via the control of charge on the phosphorene system. These results provide insight for achieving metal-free magnetism and a tunable band gap for various electronic and spintronic devices based on phosphorene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-12/jp5110938/production/images/medium/jp-2014-110938_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5110938'>ACS Electronic Supporting Info</A></P>

Advances on plant salinity stress responses in the post-genomic era: a review

Lalita Mohan Behera,Padmalochan Hembram 한국작물학회 2021 Journal of crop science and biotechnology Vol.24 No.2

Plant productivity is significantly affected by several environmental stresses. Excess amount of salt in the soil is one of the environmental stresses that affect plant growth and development adversely. Therefore, one of the significant crucial and challenging researches going on in plant science is to understand the salinity stress responses in plants. Mainly, the molecular and physiological studies promoting us to follow the salinity stress responses in various plants. Recent studies and reports on distinct and novel regulatory mechanisms and pathways involving sRNA molecules, chromosome remodelling and modification in genomic DNA. The studies enabled us to understand that the plant has evolved such a set of complex system mechanisms against severe salinity effects stress. Salt stress level causes a reduction in photosynthesis, and hikes transpiration rate in plants alternatively reduces plant biomass. Here we review our understanding of salinity stress impact on plants and various aspects of response mechanisms, metabolisms and strategies in plants. This review also highlights several response mechanisms in plants that continually takes place to withstand stress.

Nutrient and Water Management for Mitigating Arsenic Accumulation in Rice

Prasanta Kumar Patra,Sandip Hembram,Kallol Bhattacharyya,Supradip Sarkar 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

A new device concept for bacterial sensing by Raman spectroscopy and voltage-gated monolayer graphene

Nanda, Sitansu Sekhar,Kim, Bum Jun,Kim, Kwan-Woo,Nasir, Tuqeer,Park, Jaehyun,Yun, Kyusik,Hembram, K. P. S. S.,Papaefthymiou, Georgia C.,Choi, Jae-Young,Yi, Dong Kee The Royal Society of Chemistry 2019 Nanoscale Vol.11 No.17

<P>Electron-phonon coupling in monolayer graphene results in a modification of its Raman spectra upon charge transfer processes induced by interaction with its chemical environment or the presence of strain or defects in its structure. Modification of Raman spectra is examined in order to develop ultra-sensitive biosensing techniques for the detection, identification, differentiation and classification of bacteria associated with infectious diseases. Specifically, the electrochemical properties of top gated monolayer graphene on SiO2/Si substrates, in the absence and presence of interaction with Gram-positive bacteria (<I>Enterococcus faecalis</I>, <I>Bacillus subtilis</I>) and Gram-negative bacteria (<I>Escherichia coli</I> and <I>Salmonella typhimurium</I>), are probed by Raman spectroscopy in an applied voltage range from 0 V to 3 V. Bacteria and monolayer graphene interactions are thus electrostatically tuned. The resulting correlation of specific bacterial chemical properties and Raman spectral characteristics is reported, along with density functional theory simulations of the charge transfer mechanism. The intensities of the G and D Raman vibrational modes are modulated as a function of the applied voltage in the presence of bacteria, but remain unchanged in bare monolayer graphene. A fingerprint region is also identified in the range of 200 cm<SUP>−1</SUP> to 600 cm<SUP>−1</SUP>, with disulfide bonds observed at 490 cm<SUP>−1</SUP>, associated with bacterial membrane proteins. Significantly, such observations are detected even in the absence of bacterial culturing, a time-consuming step.</P>