Current Research

Our research is built on first-principles methods for electrochemical interfaces under a controlled electrode potential (the ESM and ESM-RISM methods). We continue to develop the methods themselves and apply them to fuel cells and water electrolysis, batteries, the electrochemical reduction of CO₂ and nitrogen, and corrosion. The methods are implemented in Quantum ESPRESSO and publicly available.

Method development

Efficient ESM-RISM / surface stress / grand-canonical ensemble / reaction path search

We reworked the implementation of the ESM-RISM method for efficiency (2026) and developed a dielectrically consistent RISM for the solvent response (2022). The methods now give the bias-dependent surface stress (2024) and the bias-dependent diffusion of water molecules on metal surfaces (2021), and they are combined with a reaction path search to explore elementary reactions at solid–liquid interfaces systematically (2023).

• S. Hagiwara and M. Otani, "An Efficient Implementation of the ESM-RISM Method for Simulating Electrode/Electrolyte Interfaces," J. Chem. Theory Comput. 22, 3633 (2026). doi
• S. Hagiwara, S. Ishibashi, and M. Otani, "Bias-dependent surface stress by density functional theory combined with the effective screening medium method," Phys. Rev. B 110, 155409 (2024). doi
• T. Hasegawa, S. Hagiwara, M. Otani, and S. Maeda, "A Combined Reaction Path Search and Hybrid Solvation Method for the Systematic Exploration of Elementary Reactions at the Solid–Liquid Interface," J. Phys. Chem. Lett. 14, 8796 (2023). doi
• S. Hagiwara, S. Nishihara, F. Kuroda, and M. Otani, "Development of a dielectrically consistent reference interaction site model combined with the density functional theory for electrochemical interface simulations," Phys. Rev. Materials 6, 093802 (2022). doi
• S. Hagiwara, C. Hu, S. Nishihara, and M. Otani, "Bias-dependent diffusion of a H₂O molecule on metal surfaces by the first-principles method under the grand-canonical ensemble," Phys. Rev. Materials 5, 065001 (2021). doi

Fuel cells and water electrolysis

Hydrogen evolution / oxygen reduction / oxygen evolution / Pt electrodes

First-principles molecular dynamics of the Pt/water interface under bias potential followed the dynamics of electrode reactions such as hydrogen evolution directly (2008). We went on to study the reversible redox reaction and water configuration on a positively charged Pt surface (2011), the oxygen reduction reaction on Pt by combining first-principles and kinetic calculations (2014, 2017), and hydrogen production by a molecular catalyst on a silver electrode (2017), and we also study boron monosulfide as an oxygen evolution catalyst for water electrolysis (2023).

• L. Li, S. Hagiwara, C. Jiang, H. Kusaka, N. Watanabe, T. Fujita, F. Kuroda, A. Yamamoto, M. Miyakawa, T. Taniguchi, H. Hosono, M. Otani, and T. Kondo, "Boron monosulfide as an electrocatalyst for the oxygen evolution reaction," Chem. Eng. J. 471, 144489 (2023). doi
• T. Ikeshoji and M. Otani, "Toward full simulation of the electrochemical oxygen reduction reaction on Pt using first-principles and kinetic calculations," Phys. Chem. Chem. Phys. 19, 4447 (2017). doi
• T. Ikeshoji, T. Uchida, M. Otani, and M. Osawa, "First-principles molecular dynamics simulation for electrochemical hydrogen production by 4,4′-bipyridine molecular catalyst on silver electrode," J. Electroanal. Chem. 800, 13 (2017). doi
• N. Bonnet, M. Otani, and O. Sugino, "Self-Poisoning Dynamical Effects in the Oxygen Reduction Reaction on Pt(111) from a Top-Down Kinetic Analysis," J. Phys. Chem. C 118, 13638 (2014). doi
• T. Ikeshoji, M. Otani, I. Hamada, and Y. Okamoto, "Reversible redox reaction and water configuration on a positively charged platinum surface: first principles molecular dynamics simulation," Phys. Chem. Chem. Phys. 13, 20223 (2011). doi
• M. Otani, I. Hamada, O. Sugino, Y. Morikawa, Y. Okamoto, and T. Ikeshoji, "Electrode Dynamics from First Principles," J. Phys. Soc. Jpn. 77, 024802 (2008). doi

Batteries and capacitors

MXene / graphite anodes / cathode materials

We study capacitive and pseudocapacitive storage in MXene (2020) and how its electric double layer depends on surface functional groups (2022), the thermodynamics of Li intercalation into graphite (2021), structural changes in LiCoO₂ electrodes by cluster expansion and Bayesian optimization (2023), and the kinetic suppression of anion intercalation into the conductive carbon of cathodes in high-voltage lithium batteries (2025).

• K. Nakamura, N. Takenaka, S. Hagiwara, M. Otani, and A. Yamada, "Kinetic Suppression of Anion Intercalation into Cathode Conductive Carbon in High-Voltage Lithium Batteries," ACS Appl. Mater. Interfaces 17, 61439 (2025). doi
• F. Kuroda, S. Hagiwara, and M. Otani, "Structural changes in the lithium cobalt dioxide electrode: A combined approach with cluster expansion and Bayesian optimization," Phys. Rev. Materials 7, 115402 (2023). doi
• T. Shimada, N. Takenaka, Y. Ando, M. Otani, M. Okubo, and A. Yamada, "Relationship between Electric Double-Layer Structure of MXene Electrode and Its Surface Functional Groups," Chem. Mater. 34, 2069 (2022). doi
• J. Haruyama, S. Takagi, K. Shimoda, I. Watanabe, K. Sodeyama, T. Ikeshoji, and M. Otani, "Thermodynamic Analysis of Li-Intercalated Graphite by First-Principles Calculations with Vibrational and Configurational Contributions," J. Phys. Chem. C 125, 27891 (2021). doi
• Y. Ando, M. Okubo, A. Yamada, and M. Otani, "Capacitive versus Pseudocapacitive Storage in MXene," Adv. Funct. Mater. 30, 2000820 (2020). doi

Electrochemical reduction of CO₂ and nitrogen

CO₂ reduction / nitrogen reduction / screening of alloy catalysts

Topics include the pH and voltage effects on CO₂ reduction (2020), high-throughput screening of multicomponent alloy catalysts (2024), and the electrochemical reduction of nitrogen to ammonia on IrO₂(110) (2026).

• S. Pan, M. Otani, T. Miyazaki, and J. Jiang, "Unraveling the nitrogen fixation and electrochemical reduction to ammonia on IrO₂ (1 1 0): DFT, ESM-RISM, and microkinetic simulation," J. Catal. 453, 116566 (2026). doi
• F. Kuroda, M. Ibe, and M. Otani, "Screening Multicomponent Alloys Using Evidence Theory and High-Throughput DFT Calculations for C₂-Selective eCO₂RR," J. Phys. Chem. C 128, 17302 (2024). doi
• S. Weitzner, S. Akhade, J. Varley, B. Wood, M. Otani, S. Baker, and E. Duoss, "Toward Engineering of Solution Microenvironments for the CO₂ Reduction Reaction: Unraveling pH and Voltage Effects from a Combined Density-Functional–Continuum Theory," J. Phys. Chem. Lett. 11, 4113 (2020). doi

Corrosion

Aluminum electrodes / oxide films

We evaluated the free corrosion potential of an Al electrode in acidic aqueous NaCl solution by density functional theory combined with RISM (2021), and study the charge separation induced by anion adsorption at the alumina/aluminum interface (2025).

• S. Hagiwara, T. Murata, and M. Otani, "Anion adsorption-induced charge separation at the alumina/aluminum interface," Corros. Sci. 256, 113150 (2025). doi
• K. Kano, S. Hagiwara, T. Igarashi, and M. Otani, "Study on the free corrosion potential at an interface between an Al electrode and an acidic aqueous NaCl solution through density functional theory combined with the reference interaction site model," Electrochim. Acta 377, 138121 (2021). doi