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.

Steric and electric field driven distortions in aromatic molecules: spontaneous and non-spontaneous symmetry breaking.

The structures of molecules form the cornerstone of our chemical knowledge. Lowering of symmetry in closed-shell molecules is often attributed to the Pseudo Jahn-Teller (PJT) distortions wherein non-adiabatic coupling (NAC) between the ground state and excited states creates vibrational instability along specific normal modes. Nevertheless, other factors like steric interactions are also well known in the literature to induce structural distortions.