Chemical disorder engineering enables high-voltage stable oxide cathodes over –20–25 ℃ in sodium-ion batteries

Abstract

O3-type Mn-Fe-Ni layer oxide cathodes show great commercialization potential due to their high capacities and simple synthesis. Nevertheless, simultaneously achieving high energy density and good cycling stability remains challenging. Herein, we introduce a chemical disordering strategy to create O3-Na_0.83Mn_0.35Fe_0.15Ni_0.15Cu_0.10Co_0.20Sn_0.05O₂ (MFNCCS) cathode. The chemical disordering strategy was implemented through selective multi-transition metal substitution and quenching during synthesis. The former promotes a high entropy effect, while the latter is beneficial to increasing the quenching disorder degree, functioning a synergy effect in suppressing irreversible multi-phase transitions and promoting cycling stability. As a result, the MFNCCS cathode can retain 91.6 % (∼103.3 mAh g^–1) of its capacity after 500 cycles at 200 mA g^–1, with an energy density of 285.3 Wh kg⁻¹ at the 500^th cycle, which is superior to previously reported state-of-the-art layered oxide cathodes in the voltage range of 2.0–4.3 V. Besides, it achieves stable cycling within 2.0–4.3 V over temperature range of –20 to 25 °C. This work offers new insights for high-voltage stable layered cathodes in wide-temperature SIBs.