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.

Tuning the performance of vanadium redox flow batteries by modifying the structural defects of the carbon felt electrode.

Polyacrylonitrile (PAN)-based carbon felt was subjected to N-plasma treatment to increase the heteroatom defects and reactive edge sites as a method to increase the performance in vanadium redox flow batteries (VRFBs). N-doping in the felt was mainly in the form of pyrrolic and pyridinic nitrogen. Even though the amount of oxygen functional groups on the N-plasma-treated sample was very low, the felt showed enhanced electrochemical performance for both V/V as well as V/V redox reactions.

Difference in Electrochemical Mechanism of SnO Conversion in Lithium-Ion and Sodium-Ion Batteries: Combined in Operando and Ex Situ XAS Investigations.

Conversion and alloying type negative electrodes attracted huge attention in the present research on lithium/sodium-ion batteries (LIBs/SIBs) due to the high capacity delivered. Among these, SnO is investigated intensively in LIBs due to high cyclability, low reaction potential, cost-effectiveness, and environmental friendliness. Most of the LIB electrodes are explored in SIBs too due to expected similar electrochemical performance.

Sodium vanadium titanium phosphate electrode for symmetric sodium-ion batteries with high power and long lifespan.

Sodium-ion batteries operating at ambient temperature hold great promise for use in grid energy storage owing to their significant cost advantages. However, challenges remain in the development of suitable electrode materials to enable long lifespan and high rate capability. Here we report a sodium super-ionic conductor structured electrode, sodium vanadium titanium phosphate, which delivers a high specific capacity of 147 mA h g at a rate of 0.