Electrochemical Performance of LixMn2-yFeyO4-zClz Synthesized Through In-Situ Glycine Nitrate Combustion
U.S. Army Communications Electronics Research Development and Engineering Center Aberdeen Proving Ground United States
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Lithium manganese oxide spinel is an attractive material for lithium-ion battery cathodes due to its 3D network of lithium pathways within the structure. However, this material suffers from limited cyclability as a result of structural decomposition through extended lithium insertion and deinsertion cycling. This is due to the energy barriers for removing lithium from the octahedral sites as well as the formation of Mn3 ions via the Jahn-Teller effect. The use of the glycine nitrate combustion synthesis produces small particles at reduced time and temperature during the calcining step of the synthesis process, which affords a uniform introduction of a Fe B-site modifier of AB2O4. This work incorporates chlorine to form more polarized Metal-Cl bonds to assist with liquid to solid transfer of Li during the initial Fe-doping synthesis this allows total production time to be achieved in less than 8 hours, preventing extended calcining times and at elevated temperatures which cause defect association leading to phase separation. These electrochemical cells cycle between 4.5 V and 3.5 V at 1.0 mA cm-2 10 mA gactive-1 and achieve over 250 cycles, maintaining 98 of original discharge at 71 mAh g-1. Additionally, when cycled to a deeper potential at 2.25 V the electrochemical cell delivered a capacity of 142 mAh g-1 and is completely reversible without negatively impacting further cycling. This performance allows for access to energy at extended cycling and across potential regimes.