Synthesis and electrochemical performance of micro-nano structured Li Fe1-xMnxPO4/C（0≤x≤0.05） cathode for lithium-ion batteries

摘要

cqvip:Micro-nano structured Li Fe_(1-x)Mn_xPO_4/C(0≤x≤0.05)cathodes were prepared by spray drying,followed by calcination at 700°C.The spherical Li Fe_(1-x)Mn_xPO_4/C(0≤x≤0.05)particles with the size of 0.5 to5.0μm are composed of lots of nanoparticles of 20 to 30 nm,and have the well-developed interconnected pore structure.In contrast,when Mn doping content is 3 mol%(x=0.03),the Li Fe_(0.97)Mn_(0.03)PO_4/C demonstrates maximum specific surface area of 31.30 m^2/g,more uniform pore size and relatively better electrochemical performance.The initial discharge capacities are 161.59,157.04 and 153.13 m Ah/g at a discharge rate of 0.2,0.5 and 1 C,respectively.Meanwhile,the discharge capacity retentions are～100%after 120 cycles.The improved electrochemical performance should be attributed to higher specific surface,smaller polarization voltage,and a high Li^+diffusion rate due to the micro-nano porous structure and lattice expansion produced by Mn doping.