English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In pursuit of high-energy density sodium insertion materials, polyanionic frameworks can be designed with tuneable high-voltage operation stemming from inductive effect.  Alluaudite  Na 2 Fe 2 (SO 4 ) 3  polysulfate forms one such earth-abundant compound registering the highest Fe 3+ /Fe 2+  redox potential (ca. 3.8 V vs. Na/Na + ). While this SO 4 -based system exhibits high voltage operation, it is prone to thermal decomposition and moisture attack leading to hydrated derivatives, making its synthesis cumbersome. Also, the Na–Fe–S–O quaternary system is rich with (anhydrous to hydrated) phase transitions. Herein, we demonstrate scalable aqueous-based spray drying synthesis of  alluaudite  Na 2+2 x  Fe 2− x  (SO 4 ) 3  sodium insertion material involving the formation of  bloedite  Na 2 Fe(SO 4 ) 2 ·4H 2 O as an intermediate phase. Moreover, a reversible phase transition from alluaudite to bloedite under controlled conditions of temperature and relative humidity is reported for the first time. Thermochemistry measurements revealed the enthalpies of formation (ΔH°  f  ) of  alluaudite  and  bloedite  are exothermic. Hydrated  bloedite  (ΔH°  f   =  −117.16 ± 1.10 kJ/mol) was found to be significantly more energetically stable than anhydrous alluaudite (ΔH°  f   =  −11.76 ± 1.25 kJ/mol). The calorimetric data support the observed synthesis and transformation (hydration-dehydration) pathways. Spray drying route led to spherical morphology delivering capacity ~80 mAh/g. Spray drying can be extended for rapid economic synthesis of sulfate class of battery materials.

journal of solid state electrochemistry

Aqueous spray-drying synthesis of alluaudite Na2+2xFe2−x(SO4)3 sodium insertion material: studies of electrochemical activity, thermodynamic stability, and humidity-induced phase transition