Angel Burgos, Junteng Du, Danna Yan, Yazhou Zhou, Hannah Levy, Jeong Gi Ryu, Jae Chul Kim
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引用次数: 0
Abstract
Lithium phospho-olivine cathodes operating with iron (Fe) and manganese (Mn) redox centers are considered technologically important materials that can make the development of Li-ion batteries sustainable. Although large Mn content is desirable to achieve high specific energy at a material level, the mixed olivine cathodes require particle nanostructuring and post-synthesis treatment to demonstrate reasonable energy storage properties at an electrode level. In this work, we have investigated the effect of off-stoichiometry on the electrochemical properties of a Mn-rich mixed olivine cathode material that does not require complex optimization processing. An off-stoichiometric form of LiFeMnPO is synthesized with nominal composition of LiFeMnPO. X-ray diffraction and electron microscopy indicate that off-stoichiometry leads to phase separation into stoichiometric LiFeMnPO crystalline particles with non-crystalline surface phases. The off-stoichiometric cathode has an improved specific energy of 622 Wh/kg at C/5, outperforming the stoichiometric cathode. The off-stoichiometric cathode also exhibits improved rate capability, delivering 120 mAh/g at 20C and 78 mAh/g at 40C discharge, respectively, due to reduced interfacial and charge transfer resistances. This work highlights off-stoichiometry as an effective approach to engineer Mn-rich mixed olivine cathode materials with desirable electrochemical properties, providing a practically feasible route for materials optimization.
期刊介绍:
Materials Today Energy is a multi-disciplinary, rapid-publication journal focused on all aspects of materials for energy.
Materials Today Energy provides a forum for the discussion of high quality research that is helping define the inclusive, growing field of energy materials.
Part of the Materials Today family, Materials Today Energy offers authors rigorous peer review, rapid decisions, and high visibility. The editors welcome comprehensive articles, short communications and reviews on both theoretical and experimental work in relation to energy harvesting, conversion, storage and distribution, on topics including but not limited to:
-Solar energy conversion
-Hydrogen generation
-Photocatalysis
-Thermoelectric materials and devices
-Materials for nuclear energy applications
-Materials for Energy Storage
-Environment protection
-Sustainable and green materials