Novel protonated LiCoO2 as a catalyst for the thermal decomposition of ammonium perchlorate

LiCoO2 (LCO) powders were protonated and their catalytic activity on the thermal decomposition of ammonium perchlorate (AP) was tested using differential scanning calorimetry and thermogravimetric analysis. Powders were characterized using SEM, XRD, and BET surface area analysis to quantify the morphology and structure. The thermal analysis showed that protonated powders enhanced the catalytic activity in AP decomposition over commercial and unmodified LiCoO2, Fe2O3 and Co3O4 catalyst powders.

Benjamin D. Hirt, Chase W. Wernex, Alp Sehirlioglu, Metin Örnek & Steven F. Son (2023) Novel protonated LiCoO2 as a catalyst for the thermal decomposition of ammonium perchlorate, Journal of Energetic Materials, DOI: 10.1080/07370652.2023.2287457

High-speed mapping of surface charge dynamics using sparse scanning Kelvin probe force microscopy

Unraveling local dynamic charge processes is vital for progress in diverse fields, from microelectronics to energy storage. This relies on the ability to map charge carrier motion across multiple length- and timescales and understanding how these processes interact with the inherent material heterogeneities. Towards addressing this challenge, we introduce high-speed sparse scanning Kelvin probe force microscopy, which combines sparse scanning and image reconstruction. This approach is shown to enable sub-second imaging (>3 frames per second) of nanoscale charge dynamics, representing several orders of magnitude improvement over traditional Kelvin probe force microscopy imaging rates.

Marti Checa, Addis S. Fuhr, Changhyo Sun, Rama Vasudevan, Maxim Ziatdinov, Ilia Ivanov, Seok Joon Yun, Kai Xiao, Alp Sehirlioglu, Yunseok Kim, Pankaj Sharma, Kyle P. Kelley, Neus Domingo, Stephen Jesse & Liam Collins

Engineering Multifunctional Stratified LiCoO2 Catalysts: Structural Disorder to Microstructural Exfoliation

The stratified nature of LiCoO2 (LCO) makes such materials suitable for rechargeable Li-ion batteries. The existing synthesis technology for LCO, however, results in a low surface area, low activity, and a limited density of active sites, which limit its applications in catalysis, in which the material’s functionality is determined by the reactions that occur on its surface. The present work reports a simplified and high-yield strategy for using bulk LCO in multifunctional two-dimensional (2D) catalysts.

Pachuta, Kevin G., Xiaoran Zheng, Sajjad S. Mofarah, Charles C. Sorrell, Constantine Tsounis, Jason A. Scott, Alp Sehirlioglu, Emily B. Pentzer, and Pramod Koshy. "Engineering Multifunctional Stratified LiCoO2 Catalysts: Structural Disorder to Microstructural Exfoliation." ACS Applied Energy Materials, 5 [11], 14290-14300 (2022).

CRUX: Crowdsourced Materials Science Resource and Workflow Exploration

Modern multidisciplinary materials science routinely processes scientific workflows that integrate different data resources (e.g., X-ray data, scripts, analytical results). Most of such data resources are isolated in research labs, created ad-hocly, and remain underutilized. We demonstrate CRUX, a Crowdsourced platform for materials data ResoUrces and workflow eXploration. CRUX is empowered by coherent data-workflow modeling, knowledge-based resource assembly for workflow search, and data provenance.....

Wang, Mengying, Hanchao Ma, Abhishek Daundkar, Sheng Guan, Yiyang Bian, Alpi Sehirlioglu, and Yinghui Wu. "CRUX: Crowdsourced Materials Science Resource and Workflow Exploration." In Proceedings of the 31st ACM International Conference on Information & Knowledge Management, pp. 5014-5018. 2022.

Liquid-phase exfoliation method to access cobalt oxide nanosheets in pH-neutral solutions

Two-dimensional materials have gained significant attention across the materials community due to their remarkable physical, chemical, electronic, and optical properties. With many two-dimensional materials discovered each year, investigations into their processing, scalability, and resulting properties are important to fully realize their potential in next-generation technologies....

Pachuta, Kevin, Halyna Volkova, Benjamin Hirt, Marie‐Hélène Berger, Emily Pentzer, and Alp Sehirlioglu. "Liquid‐phase exfoliation method to access cobalt oxide nanosheets in pH‐neutral solutions." Journal of the American Ceramic Society 105, no. 3 (2022): 1904-1912.

Polymer particles armored with cobalt oxide nanosheets for the catalytic degradation of bisphenol A

2D particle surfactants are attractive for the formation of highly stable emulsions and use as templates to prepare composite structures with performance properties dependent on the composition. Cobalt oxide nanosheets (CONs) are a relatively understudied class of 2D particle surfactants that can be produced ....

Escamilla, Maria, Kevin Pachuta, Kuan Huang, Michael Klingseisen, Huaixuan Cao, Huichun Zhang, Alp Sehirlioglu, and Emily Pentzer. "Polymer particles armored with cobalt oxide nanosheets for the catalytic degradation of bisphenol A." Materials Advances 3, no. 5 (2022): 2354-2363.

Superior reactivity of ferroelectric Bi2WO6/aluminum metastable intermolecular composite

Recently, the interest in exploring energetic materials beyond their basic reactive properties has grown. One such potential approach is to tune the s…

F. Xu, B. Hirt, P. Biswas, D.J. Kline, Y. Yang, H. Wang, A. Sehirlioglu, and M.R. Zachariah, "Superior reactivity of ferroelectric Bi2WO6/Aluminum metastable intermolecular composite," Che. Eng. Sci., 116898 (2021).

Ultrathin 2D-oxides: A perspective on fabrication, structure, defect, transport, electron, and phonon properties

In the field of atomically thin 2D materials, oxides are relatively unexplored in spite of the large number of layered oxide structures amenable to exfoliation. There is an increasing interest in ultrathin film oxide nanostructures from applied points of view. In this Perspective paper, recent progress in understanding...

S.K. Radha, K. Crowley, X.P.A. Gao, W.R.L. Lambrecht, H. Volkova, M.H. Berger, E. Pentzer, K. Pachuta and A. Sehirlioglu, “Ultrathin 2D-oxides: a perspective on fabrication, structural, defect, transport, electron and phonon properties.” Invited perspective paper (Journal of Applied Physics). 129, 220903 (2021).

Dimensional Stacking for Machine Learning in ToF-SIMS Analysis of Heterostructures

Output from multidimensional datasets obtained from spectroscopic imaging techniques provides large data suitable for machine learning techniques to elucidate physical and chemical attributes that define the maximum variance in the specimens. Here, a recently proposed technique of dimensional stacking is applied...

K. Abbasi, H. Smith, M. Hoffman, E. Farghadany, L.S. Bruckman, A. Sehirlioglu, “Dimensional Stacking for Machine Learning in ToF‐SIMS Analysis of Heterostructures,” Adv. Mater. Interfaces, 8 [3], 2001648 (2021).

Distinct thin film growth characteristics determined through comparative dimension reduction techniques

Reflection high energy electron diffraction (RHEED) information is critical for the growth of thin films; however, only a small percentage of the data from RHEED videos is typically used. The use o...

K. Gliebe and A. Sehirlioglu, "Distinct thin film growth characteristics determined through comparative dimension reduction techniques," J. Appl. Phys., 130, 125301 (2021).

Templated grain growth of Bi(Zn0.5Zr0.5)O3 modified BiScO3−PbTiO3 piezoelectric ceramics for high temperature applications

The TGG approach significantly improved piezoelectric properties of the BZ-BS-PT ceramic system without deteriorating the dielectric properties, which is a very promising high-performance candidate for high-temperature sensor, transducer...

E. Akca, C. Duran, B. Kowalski, and A. Sehirlioglu, "Templated grain growth of Bi(Zn0.5Zr0.5)O3 modified BiScO3-PbTiO3 piezoelectric ceramics for high temperature applications," J. Asian Ceram. Soc., (2021).

Evaluating the chemical exfoliation of lithium cobalt oxide using UV-Vis spectroscopy

Two-dimensional materials have been at the forefront of chemistry and materials science research for the past decade owing to promising applications across many fields. Improvements in exfoliation processes continually give access to new two-dimensional material compositions, demanding a deeper understanding

K. Pachuta, E. Pentzer, A. Sehirlioglu, “Evaluating the chemical exfoliation of lithium cobalt oxide using UV-Vis spectroscopy,” Nanoscale Adv., 2 5362 (2020).

Characterization of Nano-Scale Defects in Pulsed Laser Deposited (PLD) Thin Films of Li3xNd(2/3-x)(1/3-2x)TiO3 (NLTO) by Aberration Corrected HR-STEM Imaging and Dual-EELS

Characterization of Nano-Scale Defects in Pulsed Laser Deposited (PLD) Thin Films of Li3xNd(2/3-x)(1/3-2x)TiO3 (NLTO) by Aberration Corrected HR-STEM Imaging and Dual-EELS - Volume 26 Issue S2

R. Williams, N. Bagues, E. Farghadany, A. Sehirlioglu, and D. McComb, “Characterization of Nano-Scale Defects in Pulsed Laser Deposited (PLD) Thin Films of Li3xNd(2/3-x)(1/3-2x)TiO3 (NLTO) by Aberration Corrected HR-STEM Imaging and Dual-EELS,” Microscopy and Microanalysis, 26 [2], 3166 (2020).

Visualizing Charge Transport and Nanoscale Electrochemistry by Hyperspectral Kelvin Probe Force Microscopy

Charge-transport and electrochemical processes are heavily influenced by the local microstructure. Kelvin probe force microscopy (KPFM) is a widely used technique to map electrochemical potentials at the nanometer scale; however, it offers little information on local charge dynamics. Here, we implement a hyperspectral KPFM approach...

L. Collins, R.K. Vasudevan, A. Sehirlioglu, "Visualizing Charge Transport and Nanoscale Electrochemistry by Hyperspectal Kelvin Force Microscopy," ACS Appl. Mater. Interfaces, 12 [29] 33361 (2020).

Electrical Characterization and Charge Transport in Chemically Exfoliated 2D LixCoO2 Nanoflakes

Transition metal oxides often possess complex interactions between charge, spin, lattice, and orbital degrees of freedom, resulting in correlated electronic and magnetic phases. LixCoO2, one of the most commonly used cathode choices in rechargeable batteries, is a prime example of this, evidencing numerous correlated effects...

K. Crowley, K. Pachuta, S.K. Radha, H. Volkova, A. Sehirlioglu, E. Pentzer, M.H. Berger, W.R.L. Lambrecht, X.P.A Gao, "Electrical Characterization and Charge Transport in Chemically Exfoliated 2D LixCoO2 nanoflakes," J. Phys. Chem. C., 124 [38], 20693 (2020).

Effects of microstructure on fracture strength and conductivity of sintered NMC333

Sintering of LiNi0.33Mn0.33Co0.33O2 cathode material was investigated for potential application in all-electric aerospace propulsion systems utilizing new architectural concepts. All-solid-state batt...

W.H. Huddleston, F. Dynys, A. Sehirlioglu, “Effects of microstructure on fracture strength and conductivity of sintered NMC333,” J. Amer. Ceram. Soc., 103 [3], 1527 (2020).

Nickel percolation and coarsening in sintered Li4Ti5O12 anode composite

Inherently safe all-solid-state lithium-ion battery anodes with high electronic and ionic conductivity are sought to enable next-generation electric propulsion systems. In novel architectural concept...

W.H. Huddleston, F. Dynys, A. Sehirlioglu, “Nickel percolation and coarsening in sintered Li4Ti5O12 anode composite,” J. Amer. Ceram. Soc., 103 [8], 4178 (2020).

Cation deficiency associated with the chemical exfoliation of lithium cobalt oxide

This figure shows the schematic (with representated images below) for the exfoliation process of LiCoO2 by way of a two-step wet chemical treatment process. In the first step, LiCoO2 undergoes acid t...

K. Pachuta, E. Pentzer, A. Sehirlioglu, "Cation Deficiency associated with the chemical exfoliation of lithium cobalt oxide," J. Amer. Ceram. Soc., 102 (9), 5603 (2019).

Observation of Square-Planar Distortion in Lanthanide-Doped Skutterudite Crystals

Skutterudite crystals are of interest for their thermoelectric properties and in particular for the flexibility the structure offers for tuning such properties. One strategy to enhance the thermoelectric capabilities of these structures is to dope the “cage” site to disrupt phonon modes. Observation of such changes...

B.M. Hudak, W. Sun, J. Mackey, A. Ullah, A. Sehirlioglu, F. Dynys, S. Pantelides, B. Guiton, "Observation of Square-Planar Distortion in Lanthanide Doped Skutterudite Crystals," J. of Phys. Chem C., 123 (23), 14632 (2019).

Stabilization of oil-in-water emulsions with graphene oxide and cobalt oxide nanosheets and preparation of armored polymer particles

Pickering emulsions are emulsions stabilized by particles instead of small molecules or polymers, and commonly consist of oil droplets dispersed into…

K. Edgehouse, M. Escamilla, L. Wang, R. Dent, K. Pachuta, L. Kendall, P. Wei, A. Sehirlioglu, and E. Pentzer, "Stabilization of oil-in-water emulsion with graphene oxide and cobalt oxide nanosheets and preparation of armored polymer particles" J. Colloid Interface Sci, 541, 269 (2019).

Experimental search for high-temperature ferroelectric perovskites guided by two-step machine learning - Nature Communications

Experimental search for high-temperature ferroelectric perovskites is challenging due to the vast chemical space and lack of predictive guidelines. Here the authors demonstrate a two-step machine learning approach to sequentially guide experiments in search of promising perovskites with high ferroelectric Curie temperature.

P.V. Balachandran, B.A. Kowalski, A. Sehirlioglu, and T. Lookman, "Experimental search for high-temperatureferroelectric perovskites guided by two-stepmachine learning," Nature Communications, 9:1668 (2018). Editor's Highlight.

Ion blocking dip shape analysis around a LaAlO3/SrTiO3 interface

We present an analysis of the widths of the blocking dips obtained in MEIS ion blocking experiments of two LaAlO3/SrTiO3 heterostructures differing in…

D. Jalabert, H. Zaid, M.H. Berger, I. Fongkaew, W. R. L. Lambrecht, and A. Sehirlioglu, “Ion blocking dip shape analysis around a LaAlO3/SrTiO3 interface” Nuclear Inst, and Methods in Physics Research B 423 67–71 (2018).

Role of the different defects, their population and distribution in the LaAlO3/SrTiO3 heterostructure's behavior

Hetero-interfaces between epitaxial LaAlO3 films and SrTiO3 substrates can exhibit an insulator-metal transition at a critical film thickness above which a quasi-two-dimensional electron gas forms....

H Zaid, MH Berger, D Jalabert, M Walls, R Akrobetu, NJ Goble, XPA Gao, P Berger, I Fongkaew, W Lambrecht, and A Sehirlioglu, "Role of the different defects, their population and distribution in the LaAlO3/SrTiO3 heterostructure's behavior," J. Appl. Phys. 123 [15], 155304 (2018). Editor's Pick.

Anisotropic electrical resistance in mesoscopic LaAlO3/SrTiO3 devices with individual domain walls - Scientific Reports

N. Goble, R. Akrobetu, S. Sucharitakul, H. Zaid, M. –H Berger, A. Sehirlioglu, and X. Gao, “Anisotropic electrical resistance in mesoscopic LaAlO3/SrTiO3 devices with individual domain walls,” Sci. Rep, 7, 44361 (2017).

Energy-efficient ULF/VLF transmitters based on mechanically-rotating dipoles

We describe the design of miniaturized power-efficient ULF/VLF (0.3-30kHz) transmitters for underground and undersea wireless communications based on the mechanical rotation of permanently-polarized dipoles. The concept is validated using both theoretical analysis and simulations. Moreover, an integrated design...

A Madanayake, S Choi, M Tarek, S Dharmasena, S Mandal, J Glickstein, A Sehirlioglu, "Energy-efficient ULF/VLF transmitters based on mechanically-rotating dipoles," Engineering Research Conference (MERCon), 10.1109/MERCon.2017.7980487, (2017).

High temperature limitation due to onset of depoling in BiScO3–PbTiO3

Thermal depoling is investigated with impedance spectroscopy as a function of temperature and frequency for unmodified and ZnSc′ modified compositions around the morphotropic phase boundary (MPB) i...

B. Kowalski, and A. Sehirlioglu, “High Temperature Limitation due to Onset of Depoling in BiScO3 - PbTiO3”, J. Appl. Phys., 121, 064106 (2017).

The role of ceramic and glass science research in meeting societal challenges: Report from an NSF‐sponsored workshop

Under the sponsorship of the U.S. National Science Foundation, a workshop on emerging research opportunities in ceramic and glass science was held in September 2016. Reported here are proceedings of...

K.T. Faber et al. (43 authors), “The Role of Ceramic and Glass Science Research in Meeting Societal Challenges: Report from an NSF-Sponsored Workshop,” J. Amer. Ceram. Soc., 100 [5], 1777 (2017).

Core-level binding energy shifts as a tool to study surface processes on LaAlO3/SrTiO3

X-ray photoelectron spectroscopy (XPS) is used to study the adsorbed species on LalAlO3/SrTiO3 surfaces combined with computational modeling. Core lev…

I. Fongkaew, R. Akrobetu, A. Sehirlioglu, A. Voevodin, S. Limpijumnong, and W.R.L. Lambrecht, “Core-level binding energy shifts as a tool to study surface processes on LaAlO3/SrTiO3,” J. Electron Spec. Rel. Phenom., 218, 21 (2017).

Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces - Scientific Reports

H. Zaid, M.H. Berger, D. Jalabert, M. Walls, R. Akrobetu, I. Fongkaew, W. R. L. Lambrecht, N. J. Goble, X. P. A. Gao, P. Berger, and A. Sehirlioglu, “Atomic-resolved depth profile of strain and cation intermixing around LaAlO3 /SrTiO3 interfaces,” Sci. Rep., 6, 28118 (2016).

Thermoelectric characteristics of textured KSr2Nb5O15 ceramics

Effect of crystal anisotropy on thermoelectric properties of textured KSr2Nb5O15 ferroelectric ceramics is studied for the first time. Temperature dep…

C. Duran, A. Yildiz, S. Dursun, J. Mackey and A. Sehirlioglu, “Thermoelectric Characteristics of Textured KSr2Nb5O15 Ceramics,” Scripta Materialia, 112, 114 (2016).

Co x Ni4−x Sb12−y Sn y skutterudites: processing and thermoelectric properties - Journal of Materials Science

N-type and p-type skutterudite samples with the composition Co x Ni4−x Sb12−y Sn y were synthesized with composition range 0 < x < 2 and 3 < y < 5. Samples were pre-processed by solidification into ingots. Skutterudite phase formation was achieved by mechanical alloying the crushed ingots. The milled powders were consolidated to...

J. Mackey, F. Dynys, B.M. Hudak, B.S. Guiton and A. Sehirlioglu, “CoxNi4−xSb12−ySny skutterudites: processing and thermoelectric properties,” - cover article - Journal of Materials Science, 51 [13], 6117 (2016).

Aliovalent MnTi and GaTi substitution in high-temperature piezoelectric (x)Bi(Zn0.5Zr0.5)O3—(y)BiScO3—(100 – x − y)PbTiO3 - Journal of Materials Science

Aliovalent substitution of 1–2 % Mn and Ga for Ti has been carried out in the high-temperature ternary system (x)Bi(Zn0.5Zr0.5)O3—y)BiScO3—(100−x−y)PbTiO3 near the morphotropic phase boundary, specifically 2.5BZZ-37.5BS-60PT in an attempt to reduce the loss tangent. Modifications of this particular composition...

B. Kowalski, A. Sayir and A. Sehirlioglu, “Aliovalent MnTi and GaTi substitution in high temperature piezoelectric (x)Bi(Zn0.5Zr0.5)O3– (y)BiScO3 – (100-x-y)PbTiO3,” 51, 6761 (2016).

Scanning tunneling microscopy of an interfacial two-dimensional electron gas in oxide heterostructures

Using an advanced technique combining pulsed laser deposition growth of LaAlO3, LaTiO3, and SrTiO3 we effectively constructed half-integer unit cell number LaAlO3−SrTiO3 heterostructures where all interfaces are of LaO-TiO2 type, and where a two-dimensional electron gas…

I. Altfeder, H. Lee, J. Hu, R.D. Naguy, A. Sehirlioglu, A.N. Reed, A.A. Voevodin, C.-B. Eom, “Scanning tunneling microscopy of an interfacial two-dimensional electron gas in oxide heterostructures,” Phys. Rev. B., 93 (11), 115437 (2016).

Si/Ge–WSi2 composites: Processing and thermoelectric properties

Thermoelectric nano-composites composed of a Si/Ge matrix with WSi2 nano-precipitates were investigated and reductions in lattice thermal conductivity…

J.Mackey, F. Dynys, A. Sehirlioglu, "Si/Ge–WSi2 composites: Processing and thermoelectric properties," Acta Materialia, 98, 263–274 (2015).

Polymer Composites for Thermoelectric Applications

Energy budget: This Minireview summarizes recently reported polymer composites that show a thermoelectric (TE) effect and thus have potential application as thermoelectric generators and Peltier cool...

Brendan T. McGrail, Alp Sehirlioglu, and Emily Pentzer, "Polymer Composites for Thermoelectric Applications," Mini Review, Angew. Chem. Int. Ed., 54 [6], 1710 (2015).

Sputtering of molybdenum and tungsten nano rods and nodules irradiated with 150 eV argon ions

The influence of surface nano architecture on the sputtering and erosion of tungsten and molybdenum is discussed. We present an experimental investiga…

N.M. Ghoniem, Alp Sehirlioglu, Anton L. Neff, Jean-Paul Allain, Brian Williams,Reza Sharghi-Moshtaghin, "Sputtering of molybdenum and tungsten nano rods and nodulesirradiated with 150 eV argon ions," Applied Surface Science 331, 299–308 (2015).

Analytic thermoelectric couple optimization introducing Device Design Factor and Fin Factor

An analytic solution of a thermocouple has been developed in order to gain a deeper understanding of the physics of a real device. The model is establ…

J. Mackey, F. Dynys, A. Sehirlioglu, “Analytic thermoelectric couple optimization introducing Device Design Factor and Fin Factor,” Applied Energy, 134, 374 (2015).

Uncertainty analysis for common Seebeck and electrical resistivity measurement systems

This work establishes the level of uncertainty for electrical measurements commonly made on thermoelectric samples. The analysis targets measurement systems based on the four probe method. Sources...

J. Mackey, F. Dynys, A. Sehirlioglu. "Uncertainty analysis for common Seebeck and electrical resistivity measurement systems". Rev. Sci. Inst. Vol 85. 085119 (2014).

Thermoelectric properties of WSi2–SixGe1−x composites

Thermoelectric properties of the W/Si/Ge alloy system have been investigated with varying concentration levels of germanium and tungsten. The alloys w…

F. W. Dynys, A. Sayir, J. Mackey, and A. Sehirlioglu, “Thermoelectric Properties of WSi2 – SixGe(1-x) Composites,” . J. Alloys and Compounds 604 (2014) 196-203.

Characterization of the High‐Temperature Ferroelectric (100−x−y)BiScO3–(x)Bi(Zr0.5Zn0.5)O3–(y)PbTiO3 Perovskite Ternary Solid Solution

Ternary compositions based on Bi(B′B″)O3–PbTiO3-type compounds have been investigated for high-temperature piezoelectric applications. Compositions in the ternary were chosen to be near the binary mo...

B. A. Kowalski, A. Sehirlioglu, F. Dynys, and A. Sayir, "Characterization of the High-Temperature Ferroelectric (100−x−y)BiScO3–(x)Bi(Zr0.5Zn0.5)O3–(y)PbTiO3 Perovskite Ternary Solid Solution," J. Am. Ceram. Soc., 97 [2], 490-497 (2014).

Thermoelectric properties of CoxNi4-xSb12-ySny Ternary Skutterudites | 12th International Energy Conversion Engineering Conference

J.Mackey, F. Dynys, A. Sehirlioglu, "Thermoelectric properties of CoxNi4-xSb12-ySny ternary Skutterudites". 12th International Energy Conversion Engineering Conference. 4046 (2014).