Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles

Batteries based on heavier alkali ions are considered promising candidates to substitute for current Li-based technologies. In this theoretical study, we characterize the structural properties of a novel material, i.e., F-doped RbTiOPO<inline-formula><math xmlns="http://www.w3.org/1998...

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Main Authors: Adriana Bocchini, Yingjie Xie, Wolf Gero Schmidt, Uwe Gerstmann
Format: Article
Language:English
Published: MDPI AG 2023-12-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/14/1/5
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author Adriana Bocchini
Yingjie Xie
Wolf Gero Schmidt
Uwe Gerstmann
author_facet Adriana Bocchini
Yingjie Xie
Wolf Gero Schmidt
Uwe Gerstmann
author_sort Adriana Bocchini
collection DOAJ
description Batteries based on heavier alkali ions are considered promising candidates to substitute for current Li-based technologies. In this theoretical study, we characterize the structural properties of a novel material, i.e., F-doped RbTiOPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> (RbTiPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula>F, RTP:F), and discuss aspects of its electrochemical performance in Rb-ion batteries (RIBs) using density functional theory (DFT). According to our calculations, RTP:F is expected to retain the so-called KTiOPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> (KTP)-type structure, with lattice parameters of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>13.236</mn></mrow></semantics></math></inline-formula> Å, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.616</mn></mrow></semantics></math></inline-formula> Å, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>10.945</mn></mrow></semantics></math></inline-formula> Å. Due to the doping with F, the crystal features eight extra electrons per unit cell, whereby each of these electrons is trapped by one of the surrounding Ti atoms in the cell. Notably, the ground state of the system corresponds to a ferromagnetic spin configuration (i.e., <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>=</mo><mn>4</mn></mrow></semantics></math></inline-formula>). The deintercalation of Rb leads to the oxidation of the Ti atoms in the cell (i.e., from Ti<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></semantics></math></inline-formula> to Ti<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mn>4</mn><mo>+</mo></mrow></msup></semantics></math></inline-formula>) and to reduced magnetic moments. The material promises interesting electrochemical properties for the cathode: rather high average voltages above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.8</mn></mrow></semantics></math></inline-formula> V and modest volume shrinkages below 13% even in the fully deintercalated case are predicted.
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spelling doaj.art-822a644c3467464ba9ba43fd9439f1a22024-01-29T13:50:45ZengMDPI AGCrystals2073-43522023-12-01141510.3390/cryst14010005Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First PrinciplesAdriana Bocchini0Yingjie Xie1Wolf Gero Schmidt2Uwe Gerstmann3Theoretical Materials Physics, Paderborn University, 33095 Paderborn, GermanyTheoretical Materials Physics, Paderborn University, 33095 Paderborn, GermanyTheoretical Materials Physics, Paderborn University, 33095 Paderborn, GermanyTheoretical Materials Physics, Paderborn University, 33095 Paderborn, GermanyBatteries based on heavier alkali ions are considered promising candidates to substitute for current Li-based technologies. In this theoretical study, we characterize the structural properties of a novel material, i.e., F-doped RbTiOPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> (RbTiPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula>F, RTP:F), and discuss aspects of its electrochemical performance in Rb-ion batteries (RIBs) using density functional theory (DFT). According to our calculations, RTP:F is expected to retain the so-called KTiOPO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula> (KTP)-type structure, with lattice parameters of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>13.236</mn></mrow></semantics></math></inline-formula> Å, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.616</mn></mrow></semantics></math></inline-formula> Å, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>10.945</mn></mrow></semantics></math></inline-formula> Å. Due to the doping with F, the crystal features eight extra electrons per unit cell, whereby each of these electrons is trapped by one of the surrounding Ti atoms in the cell. Notably, the ground state of the system corresponds to a ferromagnetic spin configuration (i.e., <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>=</mo><mn>4</mn></mrow></semantics></math></inline-formula>). The deintercalation of Rb leads to the oxidation of the Ti atoms in the cell (i.e., from Ti<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></semantics></math></inline-formula> to Ti<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mn>4</mn><mo>+</mo></mrow></msup></semantics></math></inline-formula>) and to reduced magnetic moments. The material promises interesting electrochemical properties for the cathode: rather high average voltages above <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.8</mn></mrow></semantics></math></inline-formula> V and modest volume shrinkages below 13% even in the fully deintercalated case are predicted.https://www.mdpi.com/2073-4352/14/1/5potassium titanyl phosphaterubidium titanyl phosphateRbTiPO4FRTP:Fcathode materialsanode materials
spellingShingle Adriana Bocchini
Yingjie Xie
Wolf Gero Schmidt
Uwe Gerstmann
Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
Crystals
potassium titanyl phosphate
rubidium titanyl phosphate
RbTiPO4F
RTP:F
cathode materials
anode materials
title Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
title_full Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
title_fullStr Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
title_full_unstemmed Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
title_short Structural and Electrochemical Properties of F-Doped RbTiOPO<sub>4</sub> (RTP:F) Predicted from First Principles
title_sort structural and electrochemical properties of f doped rbtiopo sub 4 sub rtp f predicted from first principles
topic potassium titanyl phosphate
rubidium titanyl phosphate
RbTiPO4F
RTP:F
cathode materials
anode materials
url https://www.mdpi.com/2073-4352/14/1/5
work_keys_str_mv AT adrianabocchini structuralandelectrochemicalpropertiesoffdopedrbtioposub4subrtpfpredictedfromfirstprinciples
AT yingjiexie structuralandelectrochemicalpropertiesoffdopedrbtioposub4subrtpfpredictedfromfirstprinciples
AT wolfgeroschmidt structuralandelectrochemicalpropertiesoffdopedrbtioposub4subrtpfpredictedfromfirstprinciples
AT uwegerstmann structuralandelectrochemicalpropertiesoffdopedrbtioposub4subrtpfpredictedfromfirstprinciples