Facilitating reversible transition metal migration and expediting ion diffusivity via oxygen vacancies for high performance O3-type sodium layered oxide cathodes

Abstract

Currently, O3-type layered sodium transition metal oxides (NaxTMO2, TM = transition metal) are the most competitive cathodes for sodium-ion batteries (SIBs). However, affected by the scourge of irreversible TM migration...

Oxygen Vacancy Modulation towards High‐Performance Layered Oxide Cathodes for Lithium/Sodium‐Ion Batteries

“…This is because Vo as the physical defects can effectively weaken the steric hindrance and lower the inter‐layer migration energy barrier (Figure 5a). [23] Furthermore, the decreased Cr ions trapped at Na sites reduced the risk of Na + ‐diffusion blocking, thus improving the rate capability. Regarding the layered oxide cathodes for LIBs, the TM ions in Li slabs enable a robust framework [18] .…”

One‐step Surface‐to‐bulk Modification of NaCrO2 Cathode for Durable Sodium‐ion Batteries

“…The peaks located in 528.9 eV, 531.0 eV, 532.9 eV and 534.7 eV be interpreted as lattice oxygen, oxygen vacancies (O vac ), chemisorbed oxygen and Na KLL Auger, respectively. [30,[42][43][44] According to the above, chemisorbed oxygen on the material surface increases the resistance and leads to capacity fading. However, the addition of asphalt reduces chemisorbed oxygen on the surface of materials, which means carbon coating can improve air stability of NaCrO 2 .…”

“…In addition, in situ construction of oxygen vacancies has also been successfully reported by researchers. [30] Moreover, Zhou et al [31,32] developed a series of corrugated layered structure and microcube structure adjustment in the layered positive electrode of potassium ion batteries, which provide a new materials design practice for material modification.…”

Carbon Nanofiber/Na3V2(PO4)2F3 Particle Composites as a Self-Standing Cathode for High-Voltage Flexible Sodium-Ion Batteries

“…However, the operating voltages of self-standing cathodes for flexible SIBs constructed by electrospinning are relatively low, , which results in the low energy density of the self-standing cathode and limits the practical application of flexible SIBs. Currently, sodium cathode active materials can be divided into transition-metal oxide, , polyanionic compounds, , and Prussian blue analogues. , Among them, polyanionic compounds can be well-combined with electrospinning technology and are suitable as cathode active materials in self-standing cathodes. Compared to Na 3 V 2 (PO 4 ) 3 (NVP) self-standing cathodes, ,, few Na 3 V 2 (PO 4 ) 2 F 3 (NVPF) self-standing cathodes have been reported.…”