Education History

  • Ph.D Materials Science & Engineering, University of California, Los Angeles

Work Experience

Senior Professional Staff, JHU Applied Physics Laboratory


1. S.A. Langevin, M.M. Mcguire, N.Q. Le, Eugene Ragasa, Tanner Hamann, Gehn Ferguson, Christine Chung, Janna Domenico, J.S. Ko,† “Developing a nitrile-based lithium-conducting electrolytes for low temperature operation” Accepted in J. Mater. Chem. A (2022)
2. J.B. Mitchell, R. Wang, J.S. Ko, J.W. Long, V. Augustyn, “Critical role of structural water for enhanced Li+ insertion kinetics in crystalline tungsten oxides” J. Electrochem. Soc., 169, 030534 (2022)
3. P.P. Paul, B.-R. Chen, E. Dufek, J. Nelson Weker, J.S. Ko,† “Interfaces in All Solid State Li-metal Batteries: A Review on Instabilities, Stabilization Strategies, and Scalability” Energy Storage Mater., 45, 969–1001 (2022)
4. J.S. Ko,† P.Y. Meng, Zhiyong Xia, S. Holdren, “Rapid carbothermal shock enhances the double layer response of graphene oxide–carbon nanotube electrodes” Energy & Fuels, 35, 17919–17929 (2021)
5. J.S. Ko, N.Q. Le, D. Schlesinger, J.K. Johnson, Z. Xia, “Novel niobium-doped titanium oxide towards electrochemical treatment of forever chemicals” Sci. Rep., 11, 18020 (2021)
6. E. Espinosa-Villatoro, J.N. Weker, J.S. Ko,† E. Quiroga-González, “3D visualization of the evolution of relaxation times to track interfacial processes in silicon anodes for lithium ion batteries” J. Electroanal. Chem., 892, 115309 (2021)
7. C.N. Chervin, R.H. DeBlock, J.F. Parker, B.M. Hudak, N.L. Skeele, J.S. Ko, D.R. Rolison, J.W. Long, “Enhancing Li-ion capacity and rate capability in cation-defective vanadium ferrite aerogels via aluminum substitution” RSC Advances, 11, 14495–14503 (2021)
8. S.W. Kimmel, B.J. Hopkins, C.N. Chervin, N.L. Skeele, J.S. Ko, R.H. DeBlock, J.W. Long, J.F. Parker, B.M. Hudak, R.M. Stroud, D.R. Rolison, C.P. Rhodes, “Capacity and phase stability of metal-substituted α-Ni(OH)2 nanosheets in aqueous Ni–Zn Batteries” Mater. Adv., 2, 3060–3074 (2021)
9. M.B. Sassin, M.E. Helms, J.F. Parker, C.N. Chervin, J.S. Ko, D.R. Rolison, J.W. Long, “Elucidating zinc-ion battery mechanisms in freestanding carbon electrode architectures decorated with nanocrystalline ZnMn2O4” Mater. Adv., 2, 2730–2738 (2021)
10. J.S. Ko, J.M. Pierce, P.T. Shuler, K. Gerasopoulos, “Nanostructured Bi2Te3 and Sb2Te3 films prepared via MOCVD for Li-ion battery anodes” J. Alloys Compd., 859, 157847 (2021)
11. C.N. Chervin, B.J. Hopkins, A.N. Hoffmaster, N.L. Skeele, J.S. Ko, J.F. Parker, J.W. Long, D.R. Rolison, “Sustainable electrocatalytic architectures enable rechargeable zinc-air batteries with low voltage hysterisis” ACS Appl. Energy Mater., 3, 10485–10494 (2020)
12. J.S. Ko,† K. Bishop, N. Seitzman, B.R. Chen, J.N. Weker, “Highly reversible plating/stripping porous zinc anodes for multivalent zinc-ion batteries” J. Electrochem. Soc., 167, 140520 (2020)
13. R.M. Kasse, N.R. Geise, J.S. Ko, J.N. Weker, H.-G. Steinrück, M.F. Toney, “Mechanistic insight into the relationship between electrolyte additives, SEI formation, and lithium morphology in lithium metal batteries” J. Mater. Chem. A, 8, 16960–16972 (2020)
14. J.S. Ko, J.K. Johnson, P.I. Johnson, Z. Xia, “Decoupling chlorine and oxygen generation reactions in seawater using iridium-based electrocatalysts” ChemCatChem, 12, 4526–4532 (2020)
15. M.B. Sassin, A.N. Hoffmaster, A.M. Österholm, C.K. Lo, J.S. Ko, J.R. Reynolds, J.W. Long, “Integrating solution-processable conducting polymers in carbon fiber-paper: Scalable 3D electrodes for redox-based supercapacitors” ACS Appl. Polymer Mater., 2, 3234–3242 (2020)
16. C.J. Hansen, J.J. Zak, A.J. Martinolich, J.S. Ko, N.H. Bashian, B.C. Melot, J.N. Weker, K.A. See, “Multielectron cation and anion redox in Li2FeS2 and LiNaFeS2 cathodes” J. Am. Chem. Soc., 142, 6737–6749 (2020)
17. J.S. Ko,† P.P Paul, G. Wan, N. Seitzman, R.H. DeBlock, B. Dunn, M.F. Toney, J.N. Weker, “NASICON NaxV2(PO4)3 enables quasi-two-stage Na+ and Zn2+ insertion for multivalent zinc batteries” Chem. Mater., 32, 3028–3035 (2020)
18. J.S. Ko,† C.-H. Lai, J.W. Long, D.R. Rolison, B. Dunn, J.N. Weker, “Differentiating double-layer, pseudocapacitance, and battery-like mechanisms by analyzing impedance measurements in three dimensions” ACS Appl. Mater. Interfaces, 12, 14071–14078 (2020)
19. Y. Ren, J.S. Ko, R.M. Kasse, X. Song, M.F. Toney, J.N. Weker, “Hybrid nanostructured Ni(OH)2/NiO for high capacity lithium-ion battery anodes” J. Electrochem. En. Conv. Stor., 17, 041107 (2020)
20. J.F. Parker, C.R. So, M.B. Sassin, J.S. Ko, S. Jeon, C.N. Chervin, J.C. Lytle, M.E. Helms, D.R. Rolison, J.W. Long, “Pyrolitic carbon films with tunable electronic structure and surface functionality: A planar stand-in for electroanalysis of energy-relevant reactions,” ChemElectroChem, 7, 672–683 (2020)
21. R.H. DeBlock, J.S. Ko, M.B. Sassin, A.M. Hoffmaster, B.S. Dunn, D.R. Rolison, J.W. Long, “Carbon nanofoam paper enables high-rate and high-capacity Na-ion storage” Energy Storage Mater., 21, 481–486 (2019)
22. S. Jeon, R.B. Balow, G. Daniels, J.S. Ko, P.E. Pehrsson, “Conformal nanoscale zirconium hydroxide films for decomposing chemical warfare agents” ACS Appl. Nano Mater., 2, 2295–2307 (2019)
23. J.S. Ko, M.D. Donakowski, M.B. Sassin, J.F. Parker, D.R. Rolison, J.W. Long, “Deciphering charge-storage mechanisms of 3D MnOx@carbon nanofoams for rechargeable zinc-ion batteries”, MRS Commun., 9, 99–106 (2019)
24. J.S. Ko, A.B. Geltmacher, B.J. Hopkins, J.W. Long, D.R. Rolison, J.F. Parker, “Robust 3D Zn sponges enable high-power, energy-dense alkaline batteries,” ACS Appl. Energy Mater., 2, 212–216 (2018)
25. J.F. Parker, J.S. Ko, D.R. Rolison, J.W. Long, “Translating materials-level performance into device-relevant metrics for zinc-based batteries,” Joule, 2, 2519–2527 (2018)
26. J.S. Ko, J.F. Parker, M.N. Vila, D.R. Rolison, J.W. Long, “Electrocatalyzed oxygen reduction at manganese oxide nanoarchitectures: From electroanalytical characterization to device-relevant performance in composite electrodes” J. Electrochem. Soc., 165, H777–H783 (2018) *Editors’ Choice
27. J.S. Ko, H.-S. Kim, “Lithium- and sodium-ion storage properties of modulated titanate morphologies in reduced graphene oxide nanocomposites” Appl. Surf. Sci., 462, 276–284 (2018)
28. J.S. Ko, M.B. Sassin, D.R. Rolison, J.W. Long, “Deconvolving double-layer, pseudocapacitance, and battery-like charge-storage mechanisms in nanoscale LiMn2O4 at 3D carbon architectures,” Electrochim. Acta, 275, 225–235 (2018)
29. J.S. Ko, M.B. Sassin, J.F. Parker, D.R. Rolison, J.W. Long, “Combining battery-like and pseudocapacitive charge storage in 3D MnOx@carbon electrode architectures for zinc-ion cells” Sustain. Energy Fuels, 2, 626–636 (2018)
30. J.S. Ko, V.V.T. Doan-Nguyen, H.-S. Kim, X. Petrissans, R. DeBlock, C.S. Choi, J.W. Long, and B.S. Dunn, “High-rate capability of Na2FePO4F nanoparticles by enhancing surface carbon functionality for Na-ion batteries” J. Mater. Chem. A, 5, 18707–18715 (2017)
31. A.C. Serino, J.S. Ko, M.T. Yeung, J.J. Schwartz, C.B. Kang, S.H. Tolbert, R.B. Kaner, B.S. Dunn, P.S. Weiss, “Lithium ion insertion properties of solution exfoliated germanane” ACS Nano, 11, 7995–8001 (2017)
32. J.S. Ko, C.S. Choi, B. Dunn, and J.W. Long, “Electrochemical characterization of Na-ion charge-storage properties for nanostructured NaTi2(PO4)3 as a function of crystalline order” J. Electrochem. Soc., 164, A2124–A2130 (2017)
33. J.S. Ko, C.N. Chervin, M. N. Vila, P. A. DeSario, J.F. Parker, J.W. Long, and D.R. Rolison, “Electroanalytical assessment of the effect of Ni:Fe stoichiometry and architectural expression on the bifunctional activity of nanoscale NiyFe1-yOx” Langmuir, 33, 9390–9397 (2017)
34. J.S. Ko, V.V.T. Doan-Nguyen, H.-S. Kim, G. Muller, A. Serino, and B. Dunn, “Na2Ti3O7 nanoplatelets and nanosheets derived from a modified exfoliation process for use as a high capacity sodium-ion negative electrode” ACS Appl. Mater. Interfaces, 9, 1416–1425 (2017)
35. H.-S. Kim, J.B. Cook, H. Lin, J.S. Ko, S.H. Tolbert, V. Ozolins, B. Dunn, “Oxygen vacancies enhance pseudocapacitive charge storage properties of MoO3-x” Nat. Mater., 16, 454–460 (2017)
36. B.K. Lesel, J.S. Ko, B. Dunn, and S.H. Tolbert, “Mesoporous LixMn2O4 thin-film cathodes for lithium ion pseudocapacitors” ACS Nano, 10, 7572–7581 (2016)
37. J.B. Cook, H.-S. Kim, Y. Yan, J.S. Ko, B. Dunn, and S.H. Tolbert, “Mesoporous MoS2 as a transition metal dichalcogenide exhibiting pseudocapacitive Li and Na-ion charge storage”, Adv. Energy Mater., 6, 1501937 (2016)
38. C.N. Chervin, J.S. Ko, B.W. Miller, L. Dudek, A.N. Mansour, M.D. Donakowski, T. Brintlinger, P. Gogotsi, S. Chattopadhyay, T. Shibata, J.F. Parker, B.P. Hahn, D.R. Rolison, and J.W. Long, “Defective by design: Vanadium-substituted iron oxide nanoarchitectures as cation-insertion hosts for electrochemical charge storage” J. Mater. Chem. A, 3, 12059–12068 (2015)
39. V. Augustyn, E.R. White, J. Ko, G. Gruner, B.C. Regan, and B. Dunn, “Lithium-ion storage properties of titanium oxide nanosheets” Mater. Horiz., 1, 219–223 (2014)
40. I.E. Rauda, R. Buonsanti, L.C. Saldarriaga-Lopez, K. Benjauthrit, L.T. Schelhas, M. Stefik, V. Augustyn,
J. Ko, B. Dunn, U. Wiesner, D.J. Milliron, and S.H. Tolbert, “General method for the synthesis of hierarchical nanocrystal-based mesoporous materials” ACS Nano, 6, 6386–6399 (2012)

Honors and Awards

  • STFC Futures Early Career Award (2019)
  • Ernest Coleman Outstanding Mentor Award (2019)
  • National Research Council Postdoctoral Fellowship (2016)
  • NSF IGERT Fellowship (2013)