Porous LiNi0.5Mn1.5O4 microspheres with different pore conditions: Preparation and application as cathode materials for lithium-ion batteries
Here two types of LiNi0.5Mn1.5O4 (LNMO) microspheres with different pore conditions are prepared through a facile two-step method. Initially, nickel manganese carbonate microspheres are obtained through a solvothermal reaction, and then they are heated with different lithium sources to obtain the two products. Scanning electron microscopy images clearly disclose that the two types of microspheres are respectively covered with dense tinier pores and sparse larger pores while both of their interiors are constituted by nanoparticles in similar size. Nitrogen adsorption/desorption analyses indicate that their maximum pore diameters are 2.2 nm and 3.5 nm. As cathodes of lithium ion batteries, the LNMO microspheres equipped with larger pores exhibit much more excellent electrochemical performance especially in terms of rate performance, achieving a discharge capacity of 101.7 mAh g-1 even at 50C, while their counterparts only receive 14.3 mAh g-1 coupled with severe polarization. And the capacities of them respectively maintain at 102.9 and 67 mAh g-1 after 100 cycles at 20C. Their distinct performance is suggested due to both the pore parameter and its related surface area.