Amorphous Li2O2: Chemical Synthesis and Electrochemical Properties

Abstract When aprotic Li–O 2 batteries discharge, the product phase formed in the cathode often contains two different morphologies, that is, crystalline and amorphous Li 2 O 2 . The morphology of Li 2 O 2 impacts strongly on the electrochemical performance of Li–O 2 cells in terms of energy efficiency and rate capability. Crystalline Li 2 O 2 is readily available and its properties have been studied in depth for Li–O 2 batteries. However, little is known about the amorphous Li 2 O 2 because of its rarity in high purity. Herein, amorphous Li 2 O 2 has been synthesized by a rapid reaction of tetramethylammonium superoxide and LiClO 4 in solution, and its amorphous nature has been confirmed by a range of techniques. Compared with its crystalline siblings, amorphous Li 2 O 2 demonstrates enhanced charge‐transport properties and increased electro‐oxidation kinetics, manifesting itself a desirable discharge phase for high‐performance Li–O 2 batteries.