Tuesday, 21 June 2016
Riverside Center (Hyatt Regency)
Alternative active anode materials for graphite and its electrode designs for lithium ion batteries (LIBs) are under extensive investigation to meet the increasing energy storage demands. The rational design of three-dimensional (3D) hierarchical pore architectures of metal oxides and related hybrids possessing are advantageous to improved electrical conductivity and reduced volume change during charge–discharge processes. Manganese cobaltate (MnCo2O4) is considered as one of the most prospective anode material in LIBs due to its high reversible capacity and structural stability. In this work, hierarchically porous MnCo2O4 microspheres are synthesized via facile hydrothermal and chemical bath deposition methods followed by post –annealing treatment. FE-SEM and TEM analysis reveal that resulting microspheres consists of a smaller secondary nano-particles. Benefited from such mesoporous structure with much higher specific surface area, the LIBs assembled with MnCo2O4 microspheres as anodes material showed high specific capacity and excellent rate capability with superior cycle life. Such excellent electrochemical performance may originate from the reduced particle size and more active interfacial sites in the hierarchical structure. Also, the large volume variation of the anode material by the redox reactions occurs during Li+ insertion- extraction process can be effectively buffered due to the appropriate pore size of MnCo2O4 microspheres and as consequences the microsphere structure has become structurally robust which is important for enhanced electrochemical stability of anode material. As obtained results indicate that MnCo2O4 is a finer material for Li storage and with the simplicity in synthesis route its mass-production can be easily achievable which makes MnCo2O4 as competent anode material for LIBs. The overall synthesis strategy in this work is simple, cost effective and inspires for the rational design of hierarchical porous structures with enhanced properties for other spinel transition metal oxide on the nanoscale, where these spinel structures may present potential applications in the field of energy storage. This work was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant number: NRF-2013R1A1A2060638 and No. 2009-0093816).