Reduced Potential Barrier of Sodium-Substituted Disordered Rocksalt Cathode for Oxygen Evolution Electrocatalysts
Aditya Narayan Singh,
Amir Hajibabaei,
Miran Ha,
Abhishek Meena,
Hyun-Seok Kim,
Chinna Bathula,
Kyung-Wan Nam
Affiliations
Aditya Narayan Singh
Department of Energy and Materials Engineering, Dongguk University—Seoul, Seoul 04620, Republic of Korea
Amir Hajibabaei
Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50, UNIST-gil, Ulsan 44919, Republic of Korea
Miran Ha
Center for Superfunctional Materials, Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50, UNIST-gil, Ulsan 44919, Republic of Korea
Abhishek Meena
Division of Physics and Semiconductor Science, Dongguk University—Seoul, Seoul 04620, Republic of Korea
Hyun-Seok Kim
Division of Electronics and Electrical Engineering, Dongguk University—Seoul, Seoul 04620, Republic of Korea
Chinna Bathula
Division of Electronics and Electrical Engineering, Dongguk University—Seoul, Seoul 04620, Republic of Korea
Kyung-Wan Nam
Department of Energy and Materials Engineering, Dongguk University—Seoul, Seoul 04620, Republic of Korea
Cation-disordered rocksalt (DRX) cathodes have been viewed as next-generation high-energy density materials surpassing conventional layered cathodes for lithium-ion battery (LIB) technology. Utilizing the opportunity of a better cation mixing facility in DRX, we synthesize Na-doped DRX as an efficient electrocatalyst toward oxygen evolution reaction (OER). This novel OER electrocatalyst generates a current density of 10 mA cm−2 at an overpotential (η) of 270 mV, Tafel slope of 67.5 mV dec−1, and long-term stability >5.5 days’ superior to benchmark IrO2 (η = 330 mV with Tafel slope = 74.8 mV dec−1). This superior electrochemical behavior is well supported by experiment and sparse Gaussian process potential (SGPP) machine learning-based search for minimum energy structure. Moreover, as oxygen binding energy (OBE) on the surface closely relates to OER activity, our density functional theory (DFT) calculations reveal that Na-doping assists in facile O2 evolution (OBE = 5.45 eV) compared with pristine-DRX (6.51 eV).