(428e) Advances in Electronic Materials for Energy Devices: From Nanomaterials to Superstructured Materials

The development of clean energy relies heavily on material innovation. Ideal electrode materials should exhibit high electrical conductivity and large accessible surface areas, while efficient electrolytes must facilitate fast ion transfer. Our research has focused on advancing materials science and engineering— from nanomaterials to superstructured materials—for clean energy applications.[1-7] In this presentation, I will highlight our key findings on 3D graphene, alkali-metal-embedded carbon nanowalls, and superstructured materials for energy devices:

1) We discovered novel alkali metal reactions to synthesize 3D graphene materials, including honeycomb-like structured graphene, flower-like structured graphene, and surface-microporous graphene. These innovative 3D graphene structures have demonstrated exceptional performance as electrode materials in solar cells, fuel cells, batteries, and supercapacitors.

2) Utilizing our newly discovered reaction, we successfully synthesized the hypothetical alkali-metal- embedded carbon nanowalls (N@C), which exhibit ultra-high electrical conductivity and a large accessible surface area. This breakthrough resolves the long-standing trade-off between conductivity and surface area in conventional electrode materials. The N@C materials have shown outstanding performance as counter electrodes in dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs).

3) Since Wagner first demonstrated oxygen ion transfer in metal oxides with oxygen vacancies in 1943, solid electrolytes have been a subject of intense research. However, due to slow ion kinetics, these electrolytes typically require high operating temperatures above 800 °C for efficient oxygen ion transfer, limiting their practical applications. As a breakthrough, we discovered that the interface between molten alkali metal carbonates and solid electrolytes forms an ultrafast channel for oxygen ion transfer—dramatically enhancing transport rates beyond those observed in either phase alone, which reshaped the classic concept of ion transfer. Leveraging this superstructured electrolyte material, we developed a new type of fuel cell that achieves record-high open-circuit voltages and ultrahigh power densities with dry methane fuel at significantly lower temperatures (475–550 °C).

References

1) H. Su, Y. H. Hu, Thermo-photo catalytic anode process for carbonate-superstructured solid fuel cells, PNAS 121, e2314996121 (2024).

2) L. Chang, S. Chen, Y. Fei, D. J. Stacchiola, YH Hu, Superstructured NiMoO4@CoMoO4 core-shell nanofibers for supercapacitors with ultrahigh areal capacitance, PNAS 120, e2219950120 (2023).

3) H. Su, W. Zhang, Y. H. Hu, Carbonate-superstructured solid fuel cells with hydrocarbon fuels, PNAS 119, e2208750119 (2022).

4) Z. Sun, S. Fang, Y. H. Hu, 3D graphene materials: from understanding to design and synthesis control, Chem. Rev. 120, 10336 (2020).

5) L. Chang, Y. H. Hu, Breakthroughs in designing commercial-level mass-loading graphene electrodes for electrochemical double-layer capacitors, Matter 1, 596 (2019).

6) W. Wei, L. Chang, K. Sun, A. J. Pak, E. Paek, G. S. Hwang, Y. H. Hu, The bright future for electrode materials of energy devices: highly conductive porous Na-embedded carbon, Nano Lett. 16, 8029 (2016).

7) H. Wang, K. Sun, F. Tao, D. J. Stacchiola, Y. H. Hu, 3D honeycomb‐like structured graphene and its high efficiency as a counter‐electrode catalyst for dye‐sensitized solar cells, Angew. Chem. Int. Ed. 52, 9210 (2013).