Electrochemical performance of microdisc-shaped carbon-coated lithium iron phosphate with preferentially exposed (010) planes in lithium sulfate aqueous solution

A uniformly microdisc-shaped LiFePO4/C (MD-LFP/C) material with preferentially exposed (010) planes is synthesized by heating the mixture of a microdisc-shaped precursor (MD-precursor) and polyvinylpyrrolidone(PVP) in N-2 atmosphere. In particular, the MD-precursor of LiFePO4 is prepared through a simple one-pot two-step precipitation method by using ascorbic acid (AA) and PVP as morphology controlling agents. The results reveal that MD-precursor can only be obtained from the solution containing both AA and PVP. The subsequent calcination transforms the precursor into the LiFePO4/C while retaining the microdisc shape. The initial discharge capacities of the MD-LFP/C are 127, 101, 71.3 and 55.9 mA hg(-1) at 0.25, 2.5, 10 and 25 C, respectively, in a 1.0 mol dm(-3) Li2SO4 aqueous solution. The capacity retentions are 98% after 80 charge-discharge cycles and 80% after 200 cycles, respectively. The current work demonstrates that the MD-LFP/C composite can be prepared by an aqueous precipitation route and it has good electrochemical performance and stability for aqueous lithium-ion batteries. (C) 2015 Elsevier Ltd. All rights reserved.