(Digital Presentation) Renewable Energy Storage Based on the Electrochemical Cycle of Hydrogen Peroxide

Abstract

The large-scale application of intermittent renewable energy sources (such as wind and solar) requires low-cost, efficient, and zero-emission energy storage systems.1-5 Recently, we proposed an energy storage concept based on the electrochemical cycle of hydrogen peroxide (H2O2).6-8 As a proof-of-concept, we demonstrated a highly efficient PEM H2O2 electrolyzer (HPEL) for power-to-hydrogen conversion, and a unitized regenerative hydrogen peroxide cycle cell (UR-HPCC) with a round-trip efficiency (RTE) of above 90% for renewable energy storage.6, 7 The employment of platinum group metal-free (PGM-free) catalysts and other low-cost carbon materials in these devices promised a low system cost for large-scale energy storage.In this talk, we will present our recent study on the key factors affecting the performance and H2O2-cycle ability of the HPCC system. We identify the selectivity of anode catalyst in HPEL for hydrogen peroxide oxidation reaction (HPOR), the catalyst loading, and membrane thickness as the main performance-determining factors for HPEL. Specifically, the cobalt and nitrogen-doped carbon (Co-N-C) catalyst exhibits higher selectivity for HPOR over the H2O2 disproportionation reaction (HPDR) than Fe-N-C and Pt/C catalysts. Increasing the catalyst loading and membrane thickness can effectively inhibit the H2O2 crossover and thus improve the H2O2 utilization. By optimizing these factors, the crossover and disproportionation of H2O2 in the HPEL can be reduced significantly, resulting in higher system performance. On the other hand, high efficiency for H2O2 regeneration in the fuel cell component of the HPCC system is the key to the H2-H2O2 cycle. By optimizing the MEA fabrication method, catalyst loading, and operating conditions, we achieved high efficiency for H2O2 generation and remarkable power density in a PEM fuel cell. These results can guide the development of the next-generation large-scale renewable energy storage system. Acknowledgments Financial support from the State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences is greatly appreciated. This study is financially supported by the autonomous research project of SKLCC (Grant No. 2021BWZ006), ICC CAS (Grant No. 2020SC001), Key Research and Development (R&D) Projects of Shanxi Province (Grant No. 202102070301018), and Shanxi Province grant (Grant No. 202103021224442 and 20210302123011). References S. J. Davis et al., Net-zero emissions energy systems. Science 360, eaas9793 (2018).X. Yang, C. P. Nielsen, S. Song, M. B. McElroy, Breaking the hard-to-abate bottleneck in China’s path to carbon neutrality with clean hydrogen. Nature Energy 7, 955-965 (2022).A. C. Bhosale, P. C. Ghosh, L. Assaud, Preparation methods of membrane electrode assemblies for proton exchange membrane fuel cells and unitized regenerative fuel cells: A review. Renewable and Sustainable Energy Reviews 133, 110286 (2020).Z. Pu et al., Regenerative fuel cells: Recent progress, challenges, perspectives and their applications for space energy system. Applied Energy 283, 116376 (2021).J. Tang, C. Su, Y. Zhong, Z. Shao, Oxide-based precious metal-free electrocatalysts for anion exchange membrane fuel cells: from material design to cell applications. Journal of Materials Chemistry A, 9, 3151-3179 (2021).R. Ding et al.. Low-voltage hydrogen peroxide electrolyzer for highly efficient power-to-hydrogen conversion. ChemRxiv, doi:10.26434/chemrxiv-2021-9dmp4 (2021).J. Yang et al., Highly efficient unitized regenerative hydrogen peroxide cycle cell with ultralow overpotential for renewable energy storage. Journal of Power Sources 545, 231948 (2022).R. Ding et al., (Digital presentation) Hydrogen peroxide electrolyzer and reversible hydrogen peroxide cycle cell for renewable energy storage, Meeting s, The Electrochemical Society, MA2022-01, 2495 (2022).