Li3V2(PO4)3/LiFePO4 composite hollow microspheres for wide voltage lithium ion batteries

Li3V2(PO4)(3) (LVP)/LiFePO4 (LVP) composite hollow microspheres (LVP/LFP-CHMs) for lithium-ion batteries have been synthesized by a combination method, using yeast cells as both structure templates and biocarbon source. The stable heterogeneous isomorphism solid solution with superlattice structure is formed in the joint of LVP and LFP particles. A detailed analysis of the formation mechanism of solid solution with superlattice structure and the influences of different Fe:V mole ratios on the structure and electrochemical properties of composites are presented. When the LVP/LFP-CHMs with a Fe: V mole ratio of 1:3 were used as cathode material in coin cells with metallic Li as anode, the cell exhibits a discharge capacity of 221.5 mAh g(-1) for 5 cycles and discharge specific energy of 682 Wh kg(-1) at 0.1C in a wide voltage range (1.5-4.3 V). Its capacity is far higher than the capacity of unsubstituted LFP and LVP in the same wide voltage range. The energy density of this cell is about 4 times higher than that of modern commercial lithium-ion batteries (157 Wh kg(-1)). The wide voltage range not only increases the discharge capacity and energy density of cathode materials, but also could expand the range of its applications in electronic equipment. (C) 2016 Elsevier Ltd. All rights reserved.