Jaepyeong Jung

α-MnO2 nanowire catalysts with ultra-high capacity and extremely low overpotential in lithium-air batteries through tailored surface arrangement

We here report on very high capacity (11,000 mA h g(-1)), superb rate capability (4500 mA h g(-1) at 5000 mA g(-1)) and high reversibility of Li-air batteries using α-MnO2 NW catalysts mainly associated with their relatively large amount of Mn(3+) exposed on the NW surface and a unique mechanism for deposition of discharge products. Our findings of the unprecedentedly fast Li ion transport and reversible formation-decomposition of discharge products attributed to the modified surface arrangement of α-MnO2 NWs suggest a strategy for achieving high-power Li-air batteries in combination with nano-architecture tailoring.

Polymorphism-induced catalysis difference of TiO2 nanofibers for rechargeable Li–O2 batteries

The polymorphic change of TiO2 nanofiber catalysts from anatase to rutile enabled Li–O2 cells to have higher round-trip efficiency and lower overpotential followed by a better cyclic retention. This is due to enhanced catalytic activity probably associated with the smaller Li+ chemisorption energy and band gap of the rutile phase compared with the anatase phase.