Pearlescent Mica-Doped Alginate as a Stable, Vibrant Medium for Two-Dimensional and Three-Dimensional Art.

Emergent technologies are driving forces in the development of innovative art media that progress the field of modern art. Recently, artists have capitalized on the versatility of a new technology to create, restore, and modify art: additive manufacturing or three-dimensional (3D) printing. Additively manufactured art relies heavily on plastic-based materials, which typically require high heat to induce melting for workability. The necessity for heat limits plastic media to dedicated 3D printers. In contrast, biologically derived polymers such as polysaccharides used to create "bioinks" often do not require heating the material for workability, broadening the types of techniques available for printing. Here, we detail the formulation of a bioink consisting of mica pigments suspended in alginate as a new, vibrant art medium for 2D and 3D compositions. The properties that make alginate an ideal colorant binder are detailed: low cost with wide availability, nontoxicity and biocompatibility, minimal color, and an array of attractive physicochemical properties that offer workability and processing into 2D and 3D structures. Further, the chemical composition, morphology, and dispersibility of an array of mica pigment additives are characterized in detail as they pertain to the quality of an art medium. Alginate-based media with eight mica colors were formulated, where mica addition resulted in vibrantly colored inks with moderate hiding power and coverage of substrates necessary for 2D printing with thin horizontal and vertical lines. The utility of the media is demonstrated via the generation of 2D and 3D vibrant structures.

Electrolyte Effect on the Electrochemical Performance of Mild Aqueous Zinc-Electrolytic Manganese Dioxide Batteries.

Recently, mild aqueous rechargeable Zn-MnO2 batteries have attracted increasing interest for energy storage due to the low cost of Zn and Mn resources, high safety, and environmental benignity. Extensive types of MnO2 have been proposed as the cathodes in the literature, but the different reported performance and lack of a thorough understanding of reactions in MnO2 cathodes greatly hinder the practical applications of mild aqueous Zn-MnO2 batteries. Here, we revealed the correlation between the reaction mechanisms and the used electrolytes for the mild aqueous zinc-electrolytic manganese dioxide (EMD) batteries. In optimal Zn(TFSI)2-based electrolyte, the EMD cathode exhibits a mixed diffusion-controlled conversion reaction between EMD and H+ and diffusion-free "pseudocapacitance"-like reactions. This mechanism enables excellent cycling stability of an EMD cathode over 5000 cycles with a capacity retention of 94.6%. This study provides a useful insight into developing reversible MnO2 cathodes through rational control of reaction mechanisms for high performance mild aqueous Zn-MnO2 batteries.