Understanding the Effect of Solid Electrocatalysts on Achieving Highly Energy‐Efficient Lithium–Oxygen Batteries

Abstract

Nonaqueous lithium–oxygen (Li–O2) batteries are regarded as a promising electrochemical energy storage technology because of largely defeating commercial Li‐ion batteries on theoretical energy density. However, due to the electrically insulating property of Li2O2, a typical discharge product in Li–O2 batteries, high overpotential is inevitable upon charge. Nonetheless, catalysts could regulate the electrochemical formation pathways of Li2O2, and its morphology is closely bound with the energy required to dissociate. Meanwhile, in addition to Li2O2, alternative discharge products with inherently low dissociation energy can be produced by specific catalysts. Here, fundamental oxygen reduction routes in Li–O2 batteries are focused on, catalyst‐dependent geometry formation of Li2O2 is presented, and geometry‐related charge kinetics are disscussed. Products formed under specific catalysts are further explored with an emphasis on LiO2. Future directions to in situ study the electrocatalytic mechanism are subsequently proposed, and an energy system design based on oxygen redox reactions is conceived to provide new perspectives for future electrochemical energy technologies.

Keywords

• catalyst properties
• lithium–oxygen batteries
• lithium peroxide
• lithium superoxide
• product geometry