Redox: Organic Robust Radicals and Their Polymers for Energy Conversion/Storage Devices

Abstract

Persistent radicals can hold their unpaired electrons even under conditions where they accumulate, leading to the unique characteristics of radical ensembles with open-shell structures and their molecular properties, such as magneticity, radical trapping, catalysis, charge storage, and electrical conductivity. The molecules also display fast, reversible redox reactions, which have attracted particular attention for energy conversion and storage devices. This paper reviews the electrochemical aspects of persistent radicals and the corresponding macromolecules, radical polymers. Radical structures and their redox reactions are introduced, focusing on redox potentials, bistability, and kinetic constants for electrode reactions and electron self-exchange reactions. Unique charge transport and storage properties are also observed with the accumulated form of redox sites in radical polymers. The radical molecules have potential electrochemical applications, including in rechargeable batteries, redox flow cells, photovoltaics, diodes, and transistors, and in catalysts, which are reviewed in the last part of this paper.

Materials Nanoarchitectonics at Dynamic Interfaces: Structure Formation and Functional Manipulation

“…Humans have developed various types of chemistry since the 20th century, which has led to modern scientific research. Research on the development of functional systems through organic chemistry [ 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ], inorganic chemistry [ 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 ], coordination chemistry [ 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 ], supramolecular chemistry [ 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 ], polymer chemistry [ 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 ], interface chemistry [ 127 , …”