Scalable synthesis of high-voltage LiNi0.5Mn1.5O4 with high electrochemical performances by a modified solid-state method for lithium ion batteries

Abstract

Spinel LiNi0.5Mn1.5O4 is promising for next-generation lithium-ion batteries, owing to its high-voltage, low-cost, and non-toxicity. However, undesirable impurities (such as LixNi1−xO or NiO) were introduced when it was synthesized by conventional solid-state methods, due to incomplete mixing of reactants, resulting in poor performances. Here, a formic-acid-pretreated solid-state method was proposed to address this issue by adding an environmental-friendly pretreatment process to the conventional methods. Atomic-levelmixing of Li, Ni, and Mn in the precursor was achieved, thereby promoting the formation of pure LiNi0.5Mn1.5O4. The initial discharge capacity was 130.6 mAh g−1, approaching its theoretical value (147 mAh g−1). Correspondingly, 91.4% of the initial capacity was maintained after 300 cycles under 0.3C, showing long-term stability. Besides, the capacity was 99.9 mAh g−1 (76.5% of that at 0.3C) at 20C, indicating excellent rate performance. They suggest the effectiveness of our method, which promotes the development of next-generation Li-ion batteries.