Development of Bifunctional Electrocatalyst By Palladium Deposition on Modified Perovskite La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-Δ) for Li-O_2 Battery

摘要

La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ) (LSCF) perovskites have previously emerged as efficient cathode catalysts for various electrochemical devices such as lithium-air cathode, since its superior chemical stability and mixed electron-ion conductivity. LSCF exhibits good activity for the oxygen evolution reaction (OER) as cathode catalysts. However, the activity on Oxygen Reduction Reaction (ORR) is still a barrier to be utilized as a catalyst for low-temperature electrochemical devices such as lithium-air battery. Bifunctional electrocatalyst is important to reduce the large overpotential involved the sluggish kinetics of the ORR and OER at the air electrode in lithium-air battery. In this work, palladium (Pd) contents were deposited on the nano-sized LSCF surface to improve its ORR activity in lithium-air battery. When the 20 wt.% Pd/Nano-LSCF were applied to cathode catalyst in Li-O_2 battery, higher initial discharge capacity (16912 mAh g~(-1)) compared with Nano-LSCF (6707 mAh g~(-1)) was obtained. These results demonstrate the deposition of Pd can be an effective catalyst to enhance the ORR activity of perovskite LSCF.