Carbothermal Synthesis of High-Entropy Layered Oxides for Advanced Submicron-Particle Lithium Cathodes

The performance enhancement of emerging fiber lithium-ion batteries requires the synthesis of advanced materials with small particle sizes used as cathodes. In this work, a bottom-up strategy to synthesize high-entropy doped layered cathodes is developed. This method makes use of the advanced laser carbothermal technique, enabling the direct bottom-up growth of heteroatomically layered oxides with an average diameter of only 221 nm. Prevailing over the traditional LIB cathode processes, the advanced approach presented in this work reduces time cost by 75% and energy consumption by 77% while requiring no alkali solution and generating no alkali waste. The synthesized cathode material is characterized as a high-entropy hexagonal structure that effectively suppresses the interlayer rearrangement of transition metals in small-particle crystals. LIBs assembled using the prepared cathode material in the half cell not only demonstrate a high capacity retention of 92.10% after 200 cycles at 0.333C but also achieve a capacity retention of 91.65% after 300 cycles at 1 C in a full cell when graphite is utilized as a negative electrode. The full cell can also function properly within the small-volume fiber LIBs even when subjected to crumpling or bending. This work offers an insightful approach to draw the attention of the academic research and practical industrial application communities on flexible batteries.