Understanding the Correlation between Electrochemical Performance and Operating Mechanism of a Co-free Layered-Spinel Composite Cathode for Na-Ion Batteries.

Compositing different crystal structures of layered transition metal oxides (LTMOs) is an emerging strategy to improve the electrochemical performance of LTMOs in sodium-ion batteries. Herein, a cobalt-free P2/P3-layered spinel composite, P2/P3-LS-NaMnNiFeO (LS-NMNF), is synthesized, and the synergistic effects from the P2/P3 and spinel phases were investigated. The material delivers an initial discharge capacity of 143 mAh g in the voltage range of 1.

Unveiling the Electrochemical Mechanism of High-Capacity Negative Electrode Model-System BiFeO in Sodium-Ion Batteries: An In Operando XAS Investigation.

Careful development and optimization of negative electrode (anode) materials for Na-ion batteries (SIBs) are essential, for their widespread applications requiring a long-term cycling stability. BiFeO (BFO) with a LiNbO-type structure (space group 3) is an ideal negative electrode model system as it delivers a high specific capacity (770 mAh g), which is proposed through a conversion and alloying mechanism. In this work, BFO is synthesized via a sol-gel method and investigated as a conversion-type anode model-system for sodium-ion half-cells.