Rapid and Low-Carbon Emission Synthesis of Stable LiNi_0.5Mn_1.5O₄ Cathode for Li-Ion Batteries

The surging adoption of lithium-ion batteries, driven by diverse applications including electric vehicles, renewable energy storage, and portable electronics, has intensified the demand for high-energy cathode materials. The existing methods to produce cathode materials typically include high-temperature (>800 degrees C) sintering for a long period of time (>15 h), which are not only energy-intensive but also significantly contribute to CO2 emissions. This investigation presents the ultrafast microwave solid-state process to produce battery cathode materials by synthesizing high-voltage LiNi0.5Mn1.5O4 (LNMO). Benefiting from rapid direct heating with an ultrahigh heating rate (>50 degrees C), high-purity and well-defined LNMO crystals are produced in a much shorter time (2 h) as compared to the conventional heating methods (>15 h). It is revealed that microwave irradiations substantially accelerate the reaction kinetics and enhance the homogeneity of LNMO. The as-synthesized LNMO cathode delivers an excellent discharge capacity of 137.96 mAh g(-1) (at 0.05 C), and outstanding cycling stability (approximate to 63% retention over 280 cycles). The in situ characterizations elucidate the charge kinetics, suggesting high structural stability of the LNMO cathode during the reversible intercalation of Li-ions. These encouraging results pave the way toward the manufacturing of other oxide materials for energy storage and other applications using the rapid microwave method.