Air Stable O3-Type Cathode Material with Nanometer Size for Durable Low-Temperature Sodium-Ion Batteries

The application of sustainable sodium-ion batteries (SIBs) in large-scale electrical grids is primarily hindered by the bad cycling lifetime and cryogenic performance. To address these issues, we propose an O3-NaNi0.455Cu0.05Mn0.485Sb0.01O2 (NaNCMS) cathode material via Cu and Sb codoping. This NaNCMS material can preserve pristine structural and electrochemical properties when suffering from high humidity. The bulk-like shapes with nanoscale and balanced Na+ diffusion kinetics enable the NaNCMS cathode to have a high reversible capacity (134 mAh g–1 at 0.2C) and improved rate capability at room temperature. The monoclinic O′3 phase, which is responsible for huge structure reconstruction and volume change in pristine NaNi0.5Mn0.5O2, is inhibited by Cu–Sb substitution. Hence, a better cycling stability is presented for the NaNCMS cathode. Moreover, excellent electrochemical properties are exhibited at −15 °C. The low-temperature battery based on the NaNCMS cathode holds high reversible capacities of 126, 119, and 112 mAh g–1 at 0.2 0.5, and 1C, respectively. It also demonstrates a capacity retention of 72% with a final capacity of 81 mAh g–1 after 400 cycles (1C) and 62% after 1000 cycles (3C) at −15 °C.