Emerging Dual-Channel Transition-Metal-Oxide Quasiaerogels by Self-Embedded Templating

The lack of precise control of particle sizes is the critical challenge in the assembly of 3D interconnected transition-metal oxide (TMO) for newly-emerging energy conversion devices. A self-embedded templating strategy for preparing the TMO@carbon quasiaerogels (TMO@C-QAs) is proposed. By mimicking an aerogel structure at a microscale, the TMO@C-QA successfully assembles size-controllable TMO nanoparticles into 3D interconnected structure with surface-enriched carbon species. The morphological evolutions of intermediates verify that the self-embedded Ostwald ripening templating approach is responsible for the dual-channel TMO@C-QA formation. The general self-embedded templating strategy is easily extended to prepare various TMO@C-QAs, including the Co3O4@C-QA, Mn3O4@C-QA, Fe2O3@C-QA, and NiO@C-QA. Benefiting from the unparalleled 3D interconnected network of aerogels, the Co3O4@C-QA displays superior bifunctional catalytic activities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as high specific capacity and excellent long-term stability for lithium-ion battery (LIB) anode. A proof-of-concept battery-powered electrolyzer with Co3O4@C-QA cathode and anode powered by a full LIB with Co3O4@C-QA anode is presented. The battery-powered electrolyzer made of the state-of-the-art TMOs can exhibit great competitive advantages due to its supreme multifunctional energy conversion performance for future water electrolysis.