What just happened? Another day, another battery breakthrough. Researchers have unveiled a promising lithium manganese oxide battery technology that achieves an impressive energy density of 820 watt-hours per kilogram without voltage loss, outperforming conventional lithium batteries that are typically half as dense.
The lithium-ion batteries that power our phones, laptops, and electric vehicles typically use nickel and cobalt in their cathodes, which can make them expensive and environmentally unfriendly given the intensive mining they require. However, this new advancement replaces these expensive metals with manganese.
Nanostructured lithium manganese oxide cathodes can achieve an excellent energy density of 820 Wh/kg, according to a study published this week in ACS Central Science. That’s competitive with the best current nickel-based cathodes (about 750 Wh/kg) and much better than other low-cost lithium alternatives that have been attempted, with only 500 Wh/kg.
High energy density is just one piece of the puzzle. These manganese cathodes also have exceptional fast-charging capabilities, which is a huge advantage for electric vehicles where you don’t want to be tethered to a charging station for hours.
Additionally, unlike other manganese batteries, they do not appear to suffer from voltage brownout. Voltage brownout is a phenomenon where voltage decreases over time, reducing the performance and responsiveness of electronic components. This phenomenon is common in manganese-based materials.
The researchers solved this problem by controlling the crystal structure and phase transitions of lithium manganese oxide at the nanoscale. By synthesizing a nanostructured form with a monoclinic layered domain, they were able to stabilize the material in an optimal structure.
This nanoscale monoclinic crystal arrangement is the key to manganese’s high-performance potential as a battery electrode. It enables phase transitions that prevent the cathode from remaining structurally trapped in a low-capacity state.
The only downside is that manganese is quite soluble and can dissolve over time in the battery. Solving this problem remains a challenge, but researchers have found that it can be mitigated by using highly concentrated electrolytes and a lithium phosphate coating.
