Lithium ion batteries have become increasingly popular in mobile technology in recent years, and research continues to pursue alternative cathode materials that are cost effective, safe and offer high energy density. LiMn1.5Ni0.5O4 is characterized by a high 4.7 V operating voltage, enhanced safety, and good electronic and Li+ ion conductivity.             The cathode materials in this study were produced via the hydrothermal synthesis process. This procedure is used to control the stoichiometry and morphology of Mn and Ni precursors for the synthesis of LiMn1.5Ni0.5O4 cathode materials. Hydrothermal synthesis is a crystallization technique in which high temperatures and pressures are used to precipitate a mixed-metal precursor for a subsequent solid-state synthesis reaction with LiOH. The hydrothermal method produced materials in a less consistent manner than other synthesis techniques.             In this study we investigate the effects of pre-reaction solution pH on the stoichiometry, Mn3+ content, and performance of the final cathode material. Precursors were synthesized under three different reaction conditions: with a Teflon liner that had been soaked in concentrated acid, with a clean Teflon liner and deionized water as a solvent, and with a clean Teflon liner and sulfuric acid as a solvent (pH=2).             The cathode materials characterized by X-ray diffraction, Scanning electron microscopy. Cathode materials were assembled in coin cells and then tested for cycling stability. From the data we were able to determine that the acid had a negligible effect on the Mn3+, however the specific capacity of the material made in both acidic environments was considerably lower than that of the material prepared in a pH neutral solvent. Acknowledgements: MT thanks LSAMP for the Summer research academy for the support. PN thanks Prof. Manthiram, UT Austin for extending his research facilities.

Effect of pH levels on hydrothermal synthesis of sulfate-based cathode precursors for LiMn1.5Ni0.5O4 lithium-ion batteries

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.