A Layer-Structured High Entropy Oxide with Highly Reversible Fe3+/Fe4+ Redox as Advanced Cathode for Sodium Ion Batteries

Published: Jan. 1, 2024

A single-phase layer-structured high entropy oxide O3-Na(MgCu)1/12(NiCoFeMnTi)1/6O2 (HEO-MgCuNi) has been synthesized and investigated as cathode in sodium ion battery. The as-synthesized delivers a discharge capacity of 146.6 mAh g-1 at 10 mA g-1, can retain 83.2% after 700 cycles 100 between 2.0 4.1 V vs. Na+/Na. reversible O3-P3 phase-transition takes place during the charge/discharge process. In addition, electronic local structures electrochemical active centres (Ni, Cu, Co, Fe) are enormously reversible. Particularly, highly Fe3+/Fe4+ redox was revealed by X-ray absorption fine structure (XAFS). Meanwhile, Mn Ti stabilize layered without alternation their oxidation states. crystal structure, synergistically enable HEO-MgCuNi long cycle life.

Language: Английский

Tri(trimethylsilyl) phosphate as a multifunctional additive for moisture‐resistant and long‐cycling sodium‐ion batteries

EcoEnergy, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 27, 2024

Abstract The sodium hexafluorophosphate (NaPF 6 )/carbonate solution is considered as the benchmark electrolyte for sodium‐ion batteries (SIBs). However, this NaPF undergoes hydrolysis and produces acidic compounds, which deteriorate quality, corrode electrodes, jeopardize electrode interphases, eventually degrade battery performance. Herein, we introduce tris(trimethylsilyl) phosphate (TMSP) a multifunctional additive to carbonate electrolyte. We found that 10% TMSP could effectively remove H 2 O molecules inhibit hydrolysis, thus improving stability against moisture during long‐term storage. Furthermore, unique structure of promotes formation thinner, more uniform, inorganic‐rich interphases on Na 3 V (PO 4 ) (NVP) cathode hard carbon (HC) anode. Consequently, NVP cathode, HC anode, full cells demonstrate excellent cycling This work suggests tailoring formulation can provide multiple benefits boosting SIB performances, such stabilizing regulating electrolyte/electrode interphase, thereby promoting in batteries.

Language: Английский

Mixed-anion effect in topotactic syntopogenous multiphase superlattices for superior sodium-ion storage: Multi-electron redox triggered by charge compensation of anions

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: unknown, P. 158549 - 158549

Published: Dec. 1, 2024

Language: Английский