Synthesis And Properties Of La_0.6Sr_0.4Co_0.8Fe_0.2O₃ Catalyst For Lithium-air Battery

Lithium-air battery is a promising alternative energy due to its high theoretical energy densities.However,the insolubility and poor conductivity of discharge product Li2O2 will conduce to large polarization and cycle instability in lithium-air battery.The application of catalyst in the battery are beneficial oxygen reduction reaction during discharge and oxygen evolution during charge,thus the electochemical performance of lithium-air battery will be highly improved.In this paper,La_0.6Sr_0.4Co_0.8Fe_0.2O₃?LSCF?was studied and nanoparticals were synthesized by sol-gel method.The morphology and structure samples were examined by X-ray diffraction?XRD?,Brunner-Emmet-Teller?BET?mearsurement and scanning electron microscopy?SEM?.The electochemical performance of lithium-air battery based on LSCF catalyst were explored.The results are as follows:Firstly,synthesis and properties of LSCF nanoparticles catalyst.LSCF nanoparticals catalyst were synthesized by sol-gel method,the rate and cycle performance of lithium-air battery based on LSCF catalyst were tested,the result shows that the larger the current density is,the lower the discharge plateau is and the smaller capacity is.The effects of sintering temperature on the structure and electrochemical properties of LSCF catalyst were studied.When the sintering temperature is 750 °C,the lithium air battery has the best electrochemical performance which displayed an initial discharge capacity of 4804.84 mAh/g with a plateau at about 2.55 V at a current density of 50 mA/g,the cyclability was maintained for 23 cycles under a fixed discharge capacity of 500 mAh/g.Seconedly,synthesis and properties of mesoporous LSCF catalyst.Mesoporous LSCF catalyst were synthesized through hard template technique.Characterization of the catalyst by BET confirms that the mesoporous type is accumulating type.The mesoporous LSCF catalyst posses a high specific surface area of 142.15 m2/g.Compared with normal LSCF nanoparicles,the mesoporous LSCF shows better catalytic activity in the oxygen evolution reaction and higher initial potential in the oxygen reduction reaction.The battery displayed an initial discharge capacity of5753.33 mAh/g at a current density of 50 mA/g,the cyclability was maintained for 30 cycles under a fixed discharge capacity of 500 mAh/g.Such catalytic performance of mesoporous LSCF could be associated with its larger surface area and structure.