I work on thin film energy storage systems and basic materials science, developing micro-batteries for microelectronics applications and to study fundamental battery science.  I've been working at UMD since 2016 on thin film energy storage systems and fundamental materials science. I began with developing micro-batteries for applications in remote sensors, biomedical devices, and high temperature, harsh environments.

Recently I have been pursuing questions of electrochemical interface formation and kinetics, and stress-electrochemistry coupling. In my spare time, I enjoy teaching physics and nanofabrication skills, mentoring and supporting early career development, and creating physics outreach programs for elementary and middle school students to enhance critical thinking skills and STEM inclusion. 

Research interests include phenomena of electrons and ions in solid state materials, specifically at interfaces and in nanostructures, mesoscale architectures for more efficient energy capture, conversion, and storage, and improvements to the sustainability of the global energy system.

• Continuum-scale modeling in solid-state batteries
• Development of thin film battery systems
• Materials synthesis and characterization

Thin Film Platforms for Interfaces and Mechanical Coupling. Directing several projects with advisees and pursuing others personally and with collaborators, all in the vein of using thin film structures to study fundamental phenomena in batteries. 

Advisee projects: electrochemo-mechanical coupling experiments on Si electrodes, revealing the dynamical interactions between lithiation and stress gradients; thin film solid-state battery formation and characterization through a surface science approach, looking at interfacial impedance and interphase formation; modeling mechanical and chemical phenomena in 3D architectures, and effects of deposition conditions and flexible interlayers for stress relief. 

Personal projects: formation of thin film devices with artificial grain boundaries to study lithium dendrite propagation; modeling of fields and fluxes in complex 3D battery architectures for informing experiments and projecting device performance at full scale.

Collaborations: studies of band bending at battery interfaces and the impact on Li+ transport; effects of applied stresses on battery kinetics, thermodynamics, and dendrite growth.

Nanostructures for Electrical Energy Storage. Developed and characterized ALD thin film electrodes based on SnO2 as anodes for 3D microbatteries. Found a process to mix SnO2 and Sn3N4 films to produce SnOxNy films of varying composition. Thin films had greater reversibility as Li+ electrodes than bulk examples. Also studied aspects of the manufacturability of different microbattery architectures, and projected performance of various design optimizations.

 

Student Advising & Mentoring

Graduate

Undergraduate

• Y. Song, B. Bhargava, D.M. Stewart, A.A. Talin, G.W. Rubloff, P. Albertus. “Status of and opportunities in electrochemical–mechanical coupling measurements.” Joule 7, 1-23 (2023). DOI: 10.1016/j.joule.2023.03.001
• (accepted) Z. Levy, V.C. Ferrari, P. Rosas, M. Walker, K. Duddella, H. Kalpak, M. Haseman, D.M. Stewart, G.W. Rubloff, L.J. Brillson. “Lithium Spatial Distribution and Split-off Electronic Bands at Nanoscale V2O5/LiPON Interfaces.” ACS Advanced Energy Materials, XX, X, XXXX (2023). DOI: 10.1021/acsaem.2c03683
• H. Wang, N.S. Kim, Y. Song, P. Albertus, S.B. Lee, G.W. Rubloff, D.M. Stewart. “Micro-Raman Stress Characterization of Crystalline Si as a Function of the Lithiation State.” ACS Applied Materials & Interfaces, 15, 8, 10752–60 (2023). DOI: 10.1021/acsami.2c22530
• D. Fontecha, R.B. Nuwayhid, A.C. Kozen, D.M. Stewart, G.W. Rubloff, K.E. Gregorczyk. “Low temperature plasma-enhanced atomic layer deposition of sodium phosphorus oxynitride with tunable nitrogen content.” Journal of Vacuum Science & Technology A, 40, 3, 032403 (2022). DOI: 10.1116/6.0001752
• V.C. Ferrari, N.S. Kim, S.B. Lee, G.W. Rubloff, D.M. Stewart. “Co-sputtering of lithium vanadium oxide thin films with variable lithium content to enable advanced solid-state batteries.” Journal of Materials Chemistry A, 10, 23, 12518–31 (2022). DOI: 10.1039/D2TA01021F
• A. Jarry, S. Ricote, A. Geller, C. Pellegrinelli, X. Zhang, D.M. Stewart, I. Takeuchi, E. Wachsman, E.J. Crumlin, B. Eichhorn. “Assessing Substitution Effects on Surface Chemistry by in Situ Ambient Pressure X-ray Photoelectron Spectroscopy on Perovskite Thin Films, BaCexZr0.9–xY0.1O2.95 (x = 0; 0.2; 0.9).” ACS Applied Materials & Interfaces, 10, 43, 37661–70 (2018). DOI: 10.1021/acsami.8b12546
• D.M. Stewart, A.J. Pearse, N.H. Kim, E.J. Fuller, A.A. Talin, K.E. Gregorczyck, S.B. Lee, G.W. Rubloff. “Tin Oxynitride Anodes by Atomic Layer Deposition for Solid State Batteries.” Chemistry of Materials, 30, 8, 2526–34 (2018). DOI: 10.1021/acs.chemmater.7b04666 
• A.J. Pearse, T.E. Schmitt, E. Sahadeo, D.M. Stewart, A.C. Kozen, K. Gerasopoulos, A.A. Talin, S.B. Lee, G. Rubloff, K.E. Gregorczyk. “Three-Dimensional Solid-State Lithium-Ion Batteries Fabricated Via Conformal Vapor-Phase Chemistry.” ACS Nano, 12, 5, 4286–94 (2018). DOI: 10.1021/acsnano.7b08751
• D.M. Stewart, and R.J. Lad. “Enhanced Crystallinity of h-BN Films Induced by Substrate Bias During Magnetron Sputtering.” Phys. Stat. Sol. B: Basic Solid State Physics, 255, 1700458 (2017). DOI: 10.1002/pssb.201700458
• D.M. Stewart, G.P. Bernhardt, R.J. Lad. “Zirconium Diboride Thin Films for Use in High Temperature Sensors and MEMS Devices.” Proc. SPIE Microtech, 10246 © SPIE (2016). DOI: 10.1117/12.2266561
• D.M. Stewart, R.W. Meulenberg, and R.J. Lad. “Nanostructure and bonding in zirconium diboride thin films studied by X-ray spectroscopy.” Thin Solid Films, 596, 155–159 (2015). DOI: 10.1016/j.tsf.2015.06.063
• C.A. Apblett, D.M. Stewart, R.T. Fryer, J.C. Sell, H.D. III Pratt, T.M. Anderson, and R.W. Meulenberg. “In situ XANES and EXAFS analysis of redox active Fe center ionic liquids.” Electrochimica Acta, 185, 156–61 (2015). DOI: 10.1016/j.electacta.2015.09.093
• R.J. Lad, D.M. Stewart, R.T. Fryer, J.C. Sell, D.J. Frankel, G.P. Bernhardt, R.W. Meulenberg. “Electrically Conductive Pt-Zr-B and Pt-Si Thin Films for Use in High Temperature Harsh Environments.” Mat. Res. Soc. Symp. Proc. 1746 © Materials Research Society (2015).
• D.M. Stewart, D.J. Frankel, and R.J. Lad. “Growth, structure, and high temperature stability of zirconium diboride thin films.” J. Vac. Sci. Tech. A, 33, 031505 (2015). DOI: 10.1116/1.4916565
• J.C. Sell, D.M. Stewart, G.P. Bernhardt, D.J. Frankel, and R.J. Lad. “Electrically stable nanocomposite thin films formed by oxidation of Pt-ZrB2 nanolaminate templates.” J. Vac. Sci. Tech. B, 33, 021805 (2015). DOI: 10.1116/1.4914313
• D.M. Stewart, M.G. Mavros, and D.A. Micha. “Light Absorption by Crystalline and Amorphous Silicon Quantum Dots with Silver Adsorbates and Dopants.” J. Phys. Chem. C. 116, 23107–12 (2012). DOI: 10.1021/jp3075805