Impact of microwave synthesis conditions on the rechargeable capacity of LiCoPO4 for lithium ion batteries
- 797 Downloads
Lithium transition metal phosphates have the capability of improving cathode energy densities up to 800 Wh kg−1, a 27 % increase over conventional cathode active material energy densities. In this study, the effect of base-to-acid (NH4OH:H3PO4) stoichiometric conditions on the intrinsic reversible capacity of lithium cobalt phosphate (LiCoPO4) active material are investigated through microwave synthesis and electrochemical testing. Variation in solution pH results in an increase of 69 mAh g−1 in achievable capacity. X-ray diffraction results show highly crystalline LiCoPO4, with particle sizes ranging from 200 nm to greater than 1 μm based upon scanning electron microscopy. Electrochemical analysis with 1 M LiPF6 EC:EMC (1:2 v/v) provides the highest capacity over multiple cycles. A discharge capacity of 128 mAh g−1 (78 % of theoretical capacity) is achievable for intrinsic LiCoPO4 without further treatment (e.g., carbon coating) at an effective 0.1 C rate with a proper constant current–constant voltage step. Analysis of reported synthesis techniques shows that microwave synthesis yields the highest capacity for the intrinsic LiCoPO4 material to date.
KeywordsBatteries Lithium cobalt phosphate Microwave synthesis Nanomaterials
We acknowledge funding support from the Department of Energy (DE-FG36-08 GO88110) and RIT Office for Diversity & Inclusion. We also acknowledge financial support from the U.S. Government including a Grant from the Intelligence Community Postdoctoral Research Fellowship Program through funding from the Office of the Director of National Intelligence. R.A.D. acknowledges graduate student funding from a GAANN fellowship through the RIT Microsystems Engineering Ph.D. Program.
- 3.Howell D (2009) Progress Report for Energy Storage Research and Development. U.S. Department of Energy, Washington, DCGoogle Scholar
- 29.Dimesso L, Forster C, Jaegermann W, Khanderi JP, Tempel H, Popp A, Engstler J, Schneider JJ, Sarapulova A, Mikhailova D, Schmitt LA, Oswald S, Ehrenberg H (2012) Developments in nanostructured LiMPO4 (M = Fe, Co, Ni, Mn) composites based on three dimensional carbon architecture. Chem Soc Rev 41(15):5068–5080. doi: 10.1039/c2cs15320c CrossRefGoogle Scholar