Understanding the fundamentals of redox mediators in Li-O2 batteries: a case study on nitroxides.

摘要: The development of aprotic lithium-oxygen (Li-O2) batteries suffers from high charging overvoltages. Dissolved redox mediators, like nitroxides, providing increased energy efficiency and longer lifetime are promising tools to overcome this challenge. Since auspicious concept is still in its infancy, the underlying chemical reactions as well impact different (electro)chemical parameters poorly understood. Herein, we derive an electrochemical model for reactions, which validated by potentiostatic measurements. elucidates major factors including basic cell properties mediator. applied class systematically investigated using derivatives TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), AZADO (2-azaadamantane-N-oxyl), azaphenalene based nitroxide. nitroxides electrochemically characterized cyclic voltammetry their performance mediators studied Li-O2 with ether-based electrolyte. Based on presented model, profiles nitroxide correlated molecular structures.