Collective, bifunctional 1D CNT/2D TMOH hybrid sponge as high-capacity and long-cycle Li-O2 cathode

Abstract

Owing to their bifunctional catalytic advantages such as oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), two-dimensional (2D) transitional metal hydroxide (TMOH) nanosheets exhibit promising catalytic activity as metal-air batteries electrodes, however currently it remains challenging to achieve both high capacity and long cyclic life. Here, we combine 2D TMOHs with 1D carbon nanotubes (CNTs) to construct a mutually interpenetrated hybrid structure, in which the CNT network acts as a porous conductive skeleton and the TMOH sheets behave as a bifunctional catalytic substrate to deposit discharge product effectively. Such a collective function results in superior properties when serving as a lithium-oxygen cathode, exhibiting long cycle life of 300 cycles under areal capacity limit of 0.5 mAh cm−2, and 178 cycles (∼1400 hours) even at 2 mAh cm−2. Our mixed-dimensional hybrid electrodes offer a promising route in developing high performance electrochemical catalysis and energy storage systems.