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

Abstract

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-NaNi 0.455 Cu 0.05 Mn 0.485 Sb 0.01 O 2 (NaNCMS) cathode material via Cu and Sb codoping. This NaNCMS material can preserve pristine structural and electrochemical properties when suffering from high humidity. The bulklike 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 NaNi 0.5 Mn 0.5 O 2 , 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.