Chemical modification of ordered/disordered carbon nanostructures for metal hosts and electrocatalysts of lithium-air batteries

Abstract

Although lithium-air batteries (LABs) are considered the promising alternative of existing lithium–ion batteries owing to their high energy density of 11 680 W h kg−1, their practical applications are limited by the technical issues, such as unstable solid electrolyte interface and dendrite formation from metal anode and insufficient bifunctional activities and durability from cathode catalyst. In order to resolve these bottlenecks, carbon nanostructures have been investigated owing to their high surface area, excellent electrical conductivity, electrochemical stability, and various modification chemistries. Herein, we comprehensively review a recent progress on the design of carbon nanostructures for their applications into metal hosts, protection layers, and bifunctional electrocatalysts of LABs. The correlation between the crystalline, electronic, porous, and chemical structures and the electrochemical properties of carbon nanomaterials are discussed depending on their classification and characteristics. Various chemical modifications, such as morphological control, hierarchical architecturing, heteroatom incorporation, and the formation of composites, for the improved electrochemical performances of anode and cathode will be also addressed. Furthermore, we deal with the perspectives for the ongoing obstruction and future guidance.