Open mesoporous spherical shell structured Co₃O₄ with highly efficient catalytic performance in Li-O₂ batteries

An open mesoporous spherical shell structured (OMSS) Co₃O₄ was designed and synthesized through a two-step process. The OMSS Co₃O₄ with a diameter around 1 μm is constructed from a large number of nanoparticles mainly with (111) preferential exposed crystal planes. Superior catalytic activity for oxygen evolution reaction (OER) can be manifested in Li-O₂ batteries with the charge voltage platform reduced to ∼3.6 V. An outstanding performance of cycling stability was also achieved with a cut-off specific capacity of 1000 mA h g^-1 over 60 cycles. The fantastic cycling performance may be attributed to the open mesoporous spherical shell structure with high specific surface area which improves the transport capability of oxygen, increases the active sites and the sedimentary space of discharge products. It almost gets the highest cycling performance among metal oxide catalysts used in Li-O₂ batteries reported to date.