Integrated Polyphenol-Based Hydrogel Templating Method for Functional and Structured Oxidic Nanomaterials

A straightforward fabrication method for tunable nanomaterials remains a key objective in the research areas of template chemistry, catalysis, and energy storage materials. A growing focus in materials chemistry is the development of structuring methods that are simple, scalable, and, at the same time, feasible with environmentally benign chemicals. We present a hydrogel-mediated templating method that yields customizable, porous transition-metal oxides. The protocol is extremely simple and includes predominately naturally occurring compounds. For example, the incorporation of sacrificial polymer latex into a polyphenolic hydrogel network produces xerogel composites with various filler contents. Voids are generated simultaneously during the pyrolysis of the dried gel, allowing for controlling the three-dimensional (3D) arrangement of titania nanocrystals. As a proof of concept, we use the produced macroporous titania as a negative electrode (anode) material in lithium-ion batteries. We demonstrate that the gel-derived macroporous anatase significantly reduces the capacity loss compared to its commercial or nonporous analogues. The modularity of this one-pot templating protocol is further demonstrated by the fabrication of titanate nanostructures and porous zirconia.