Reversible facile Rb+ and K+ ions de/insertion in a KTiOPO4-type RbVPO4F cathode material

In this paper, we report on a novel RbVPO4F fluoride phosphate, which adopts the KTiOPO4 (KTP) type structure and complements the AVPO4F (A = alkali metal) family of positive electrode (cathode) materials for metal-ion batteries. RbVPO4F was synthesized via a freeze-drying assisted solid-state route...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2018, Vol.6 (29), p.14420-14430
Main Authors: Fedotov, Stanislav S, Aleksandr Sh Samarin, Nikitina, Victoria A, Aksyonov, Dmitry A, Sokolov, Sergey A, Zhugayevych, Andriy, Stevenson, Keith J, Khasanova, Nellie R, Abakumov, Artem M, Antipov, Evgeny V
Format: Article
Language:English
Subjects:
Alkali metals
Batteries
Cathodes
Chemical synthesis
Computer applications
Diffusion
Electrochemistry
Electrode materials
Electrodes
Freeze drying
Insertion
Ion transport
Ionic mobility
Metal ions
Metals
Personal computers
Potassium
Potassium titanyl orthophosphate
Propylene
Rubidium
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this paper, we report on a novel RbVPO4F fluoride phosphate, which adopts the KTiOPO4 (KTP) type structure and complements the AVPO4F (A = alkali metal) family of positive electrode (cathode) materials for metal-ion batteries. RbVPO4F was synthesized via a freeze-drying assisted solid-state route and characterized via structural, computational and electrochemical methods. RbVPO4F represents the first example of reversible electrochemical Rb+ de/insertion in a crystalline oxypolyanionic framework. The electrochemical measurements on RbVPO4F in a three-electrode cell configuration in RbClO4-saturated propylene carbonate (PC) electrolyte revealed that the material exhibits reversible Rb+ de/insertion within the 0.4–1.3 V vs. Ag+/Ag potential range (∼3.9–4.8 V vs. K+/K) displaying rather high diffusion coefficients of (0.3–1.0) × 10−11 cm2 s−1 comparable to those of K+ in KVPO4F that supports reasonably fast ionic mobility in the KTP structure despite the large ionic radius of the Rb+ ions. The energy barriers of Rb+ ion transport are exceptionally low not exceeding 0.2 eV along the c-axis and correlating well with diffusion coefficients estimated using the DFT+U-NEB methodology and with the experimentally determined transport properties. These results suggest a new paradigm for the development of materials that support many monovalent ion reversible de/insertion processes in a single prototypical structural oxypolyanionic framework.
ISSN:2050-7488
2050-7496
DOI:10.1039/c8ta03839b