High-rate cyclability and stability of LiMn2O4 cathode materials for lithium-ion batteries from low-cost natural β-MnO2

The implementation of spinel LiMn2O4 in lithium-ion batteries has been long established commercially and well-reported academically. Nowadays, most commercial spinel LiMn2O4 electrodes are synthesized by electrolytic manganese dioxide (EMD) precursors. However, using earth-abundant and inexpensive pyrolusite (beta-MnO2) as reported in this work, offers several advantages. The synthesis of spinel LiMn2O4 using beta-MnO2 precursors by solid-state reaction followed by thermal calcination under air generated micro rod-like lithium impregnated powders. Examining the electrochemical performance of these active materials upon Li-ion intercalation registered an initial specific discharge capacity of 95 mA h g(-1). The synthesized cathode material was able to cycle at high rates (up to 9C) while retaining half of its initial discharge capacity, with just an overall drop reaching 7% of its capacity. Distinctive stability after 500 cycles at combined charge/discharge rates was recorded with a minute irreversible capacity loss and an overall capacity drop of 3%. This work authenticates the use of natural pyrolusite ingredients as a precursor for spinel LiMn2O4 synthesis besides providing economic and ecological assertions with the synthesis technique implemented.