Grain-Boundary-Free Super-Proton Conduction of a Solution-Processed Prussian-Blue Nanoparticle Film

Angewandte Chemie - International Edition

5 years ago

Grain-Boundary-Free Super-Proton Conduction of a Solution-Processed Prussian-Blue Nanoparticle Film

Takanari Togashi, Teppei Yamada, Masato Kurihara, Manabu Ishizaki, Katsuhiko Kanaizuka, Kenta Ono, Hiroshi Kitagawa

A porous crystal family has been explored as alternatives of Nafion films exhibiting super-proton conductivities of ≥10−2 S cm−1. Here, the proton-conduction natures of a solution-processed film of nanoparticles (NPs) have been studied and compared to those of a Nafion film. A mono-particle film of Prussian-blue NPs is spontaneously formed on a self-assembled monolayer substrate by a one-step solution process. A low-temperature heating process of the densely packed, pinhole-free mono-particle NP film enables a maximum 105-fold enhancement of proton conductivity, reaching ca. 10−1 S cm−1. The apparent highest conductivity, compared to previously reported data of the porous crystal family, remains constant against humidity changes by an improved water-retention ability of the film. In our proposed mechanism, the high-performing solution-processed NP film suggests that heating leads to the self-restoration of hydrogen-bonding networks throughout their innumerable grain boundaries. A densely packed, pinhole-free mono-particle film of Prussian blue (PB) nanoparticles is formed on a substrate. Low-temperature heating of the film leads to an up to 105-fold enhancement of proton conductivity, reaching circa 10−1 S cm−1. The high-performing solution-processed film suggests that heating enables the self-restoration of hydrogen-bonding networks throughout their innumerable grain boundaries.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201701759