Prof. Yubin Chen
Xi’an Jiaotong University, China
Title: Solar-driven decoupled electrolysis for flexible co-production of hydrogen and electricity
Abstract:
Decoupled electrolysis for hydrogen production with the aid of a redox mediator enables two half-reactions operating at different rates, times, and spaces, which offers great flexibility in operation. Herein, a pre-protonated vanadium hexacyanoferrate (p-VHCF) redox mediator is synthesized. It offers a high reversible specific capacity up to 128 mAh g-1 and long cycling performance of 6000 cycles with capacity retention about 100% at a current density of 10 A g-1 due to the enhanced hydrogen bonding network. By using this mediator, a membrane-free water electrolytic cell is built to achieve decoupled hydrogen and oxygen production. More importantly, a decoupled electrolysis system for hydrogen production and hydrazine oxidation is constructed, which realizes not only separate hydrogen generation but electricity generation through the p-VHCF-N2H4 liquid battery. Therefore, this work enables the flexible energy conversion and storage with hydrogen production driven by solar cell at day-time and electricity output at night-time.
Further, an integrated hydrogen-oxygen-electricity cogeneration system featuring a bipolar membrane-assisted electrolyzer and a Na-Zn ion battery was established with sodium nickelhexacyanoferrate (NaNiHCF) and Zn2+/Zn dual redox electrodes. The bipolar membrane-assisted electrolyzer enables to produce H2 and O2 in different time and space with almost 100% Faradic efficiency at 100 mA. Then, the charged NaNiHCF and Zn electrodes after the electrolysis processes formed a Na-Zn ion battery, which can generate electricity with an average cell voltage of 1.75 V at 10 mA. This device also achieved a well-matched solar driven system to convert and store the intermittent solar energy by connecting with Si photovoltaic modules, realizing flexible conversion from renewables to hydrogen and electric energy.
References
(1) Lv F, Wu J, Liu X, Zheng Z, Pan L, Zheng X, Guo L, Chen Y*. Decoupled electrolysis for hydrogen production and hydrazine oxidation via high-capacity and stable pre-protonated vanadium hexacyanoferrate. Nature Communications, 2024, 15: 1339.
(2) Wu J, Lv F, Pan L, Chen Y*. Decoupled Water Electrolysis via VO2+/VO2+ Redox Mediator for 35 MPa High-Pressure Hydrogen Production. ACS Sustainable Chemistry & Engineering, 2023, 11, 49, 17199-17205.
(3) Zheng X, Lv F, Liu X, Zheng Z, and Chen Y*. Decoupled alkaline water electrolysis by K0.5MnO2-Ti mediator via K-ion insertion/extraction. Chemical Communications, 2023, 59: 2138-2141.
(4) Lv F, Qin Z, Wu J, Pan L, Liu L, Chen Y*, and Zhao Y*. Decoupled Water Electrolysis Driven by 1 cm2 Single Perovskite Solar Cell Yielding a Solar‐to‐Hydrogen Efficiency of 14.4%. ChemSusChem, 2023, 16(1): e202201689.
Biography:
Yubin Chen is a professor at the State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University. His main research focuses on solar energy conversion and water electrolysis for hydrogen production. He has published more than 80 academic articles in Nature Communications, Angewandte Chemie International Edition, ACS Energy Letters, etc. He was selected as a Top 1% Highly Cited Author by the Royal Society of Chemistry (RSC) in 2019, and has won the First Prize of Shaanxi Provincial Science and Technology Award in 2016 and Shaanxi Provincial Higher Education Teaching Prize in 2023.