Crystal Structure and Li-Ion Transport in Li<sub>2</sub>CoPO<sub>4</sub>F High-Voltage Cathode Material for Li-Ion Batteries

Fedotov, Stanislav S.; Kabanov, Artem A.; Kabanova, Natalia A.; Блатов, В. А.; Zhugayevych, Andriy; Abakumov, Artem M.; Khasanova, Nellie R.; Antipov, Evgeny V.

doi:10.1021/acs.jpcc.6b11027

Cited by 37 publications

(23 citation statements)

References 43 publications

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“…A combination of a polyanion group (XO 4 m− , X = Si, P, S) and fluoride anions might present a viable strategy to further enhance the redox potential owing to the highest electronegativity of fluorine 32,33 . Indeed, fluoride-containing polyanion materials typically provide higher electrode potentials in comparison to their fluoride-free counterparts (for instance, LiTi 2 (PO 4 ) 3 -2.4 V (ref.…”

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Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

et al. 2020

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The rapid progress in mass-market applications of metal-ion batteries intensifies the development of economically feasible electrode materials based on earth-abundant elements. Here, we report on a record-breaking titanium-based positive electrode material, KTiPO 4 F, exhibiting a superior electrode potential of 3.6 V in a potassium-ion cell, which is extraordinarily high for titanium redox transitions. We hypothesize that such an unexpectedly major boost of the electrode potential benefits from the synergy of the cumulative inductive effect of two anions and charge/vacancy ordering. Carbon-coated electrode materials display no capacity fading when cycled at 5C rate for 100 cycles, which coupled with extremely low energy barriers for potassium-ion migration of 0.2 eV anticipates high-power applications. Our contribution shows that the titanium redox activity traditionally considered as "reducing" can be upshifted to near-4V electrode potentials thus providing a playground to design sustainable and cost-effective titanium-containing positive electrode materials with promising electrochemical characteristics.

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confidence: 99%

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

et al. 2020

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“…A previous theoretical work predicted a three-step reaction of Li 2 CoPO 4 F, but the observation of four redox pairs suggests another reaction mechanism. [51] Superior reversibility of the optimized cell design was also demonstrated in the charge-discharge tests of Li 2 CoPO 4 F/Li half-cells (Figure S11) and Li 2 CoPO 4 F/graphite full-cells ( Figure S12) with commercial electrolyte.…”

Section: Cell Design For High-voltage Batteriesmentioning

confidence: 75%

A 4.8 V Reversible Li₂CoPO₄F/Graphite Battery Enabled by Concentrated Electrolytes and Optimized Cell Design

Yamada

2020

Batteries & Supercaps

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Elevating the voltage of lithium‐ion batteries (currently 3.8 V) is a simple and pragmatic way to achieve high‐density energy storage. Many so‐called “5 V‐class” cathodes have been discovered over the past decade; however, they have been studied below 5 V (vs. Li/Li+) because of the severe oxidation of electrolytes and other cell components. Here, highly reversible charge‐discharge cycling of Li2CoPO4F/graphite full‐cells up to a cut‐off voltage of 5.2 V is demonstrated for the first time. This result is achieved with synergetic effects of an optimized cell design and a newly designed concentrated electrolyte based on LiBF4, propylene carbonate (PC), and fluoroethylene carbonate (FEC). As an electrolyte design rationale, two important properties of high oxidation stability and anode‐passivation ability are clearly allocated for LiBF4 and FEC, respectively. Besides, all other cell components (e. g., conductive carbon, separator, and binder) are reconsidered and customized for use at >5 V. The new concentrated electrolyte and optimized cell design presented here will pave the way for developing over‐5 V rechargeable batteries.

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“…Synthesis: The LiNaCoPO 4 F samples with 2D and 3D structures were synthesized via a two‐step freeze‐drying assisted solid‐state method. At first, LiCoPO 4 was prepared as described in and then mixed with 3 % excess of NaF (99.9 %, Sigma‐Aldrich), pressed into pellets and annealed under Ar flow at different temperatures from 500 to 650 °C depending on the structure for 1 h with subsequent quenching to room temperature (under Ar atmosphere).…”

Section: Methodsmentioning

confidence: 99%

Tuning the Crystal Structure of A₂CoPO₄F (A = Li, Na) Fluoride‐Phosphates: A New Layered Polymorph of LiNaCoPO₄F

et al. 2019

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Co-containing fluoride-phosphates are of interest in sense of delivering high electrode potentials and attractive specific energy values as positive electrode materials for rechargeable batteries. In this paper we report on a new Co-based fluoride-phosphate, LiNaCoPO 4 F, with a layered structure (2D), which was Rietveld-refined based on X-ray powder diffraction data [P2 1 /c, a = 6.83881(4) Å, b = 11.23323(5) Å, c = 5.07654(2) Å, = 90.3517(5)°, V = 389.982(3) Å 3 ] and validated by electron diffraction and high-resolution scanning transmission electron microscopy. The differential scanning calorimetry measurements revealed that 2D-LiNaCoPO 4 F forms in a narrow temperature range of 520-530°C and irreversibly converts to the known 3D-LiNaCoPO 4 F modification (Pnma) above 530°C. The non- [a] 4365 carbon-coated 2D-LiNaCoPO 4 F shows reversible electrochemical activity in Li-ion cell in the potential range of 3.0-4.9 V vs. Li/Li + with an average potential of ≈ 4.5 V and in Na-ion cell in the range of 3.0-4.5 V vs. Na/Na + exhibiting a plateau profile centered around 4.2 V, in agreement with the calculated potentials by density functional theory. The energy barriers for both Li + and Na + migration in 2D-LiNaCoPO 4 F amount to 0.15 eV along the [001] direction rendering 2D-LiNaCoPO 4 F as a viable electrode material for high-power Li-and Na-ion rechargeable batteries. The discovery and stabilization of the 2D-LiNaCoPO 4 F polymorph indicates that temperature influence on the synthesis of A 2 MPO 4 F fluoride-phosphates needs more careful examination with perspective to unveil new structures. trode potential to much higher values in comparison to oxides. Moreover, a better ionic transport is expected owing to a lower affinity of alkali metals towards fluoride than oxide anions. A much richer structural diversity of fluoride-phosphates offers manifold options for tuning the electrochemical properties. [4] Among fluoride-phosphates, the A 2 MPO 4 F (A = Li, Na; M = Mn, Fe, Co, Ni) family provides one of the largest playgrounds for searching new cathode materials. [5] From the electrochemical standpoint, this class also regains interest due to a theoretical possibility of multi-electron redox transitions enabling reversible de/intercalation of more than one alkali ion per transition metal center.The wide structural variety of A 2 MPO 4 F is primarily originated from multiple options in playing with the chemical composition of the cation sublattice. Depending on the nature of the A and M metals, MO 4 F 2 octahedra (key building blocks) constitute various types of linkage: from corner-sharing to facesharing and their combinations. Since A and M sites can be populated by more than one element type, altering their average ionic radius by substitutions might also influence the preferable MO 4 F 2 connectivity thus preserving a specific structural type for new chemical compositions or even giving rise to new structures.Corner-shared MO 4 F 2 octahedra are only characteristic to Na 2 MnPO 4 F [6,7] and its limited solid solu...

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Crystal Structure and Li-Ion Transport in Li₂CoPO₄F High-Voltage Cathode Material for Li-Ion Batteries

Cited by 37 publications

References 43 publications

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

A 4.8 V Reversible Li₂CoPO₄F/Graphite Battery Enabled by Concentrated Electrolytes and Optimized Cell Design

Tuning the Crystal Structure of A₂CoPO₄F (A = Li, Na) Fluoride‐Phosphates: A New Layered Polymorph of LiNaCoPO₄F

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Crystal Structure and Li-Ion Transport in Li2CoPO4F High-Voltage Cathode Material for Li-Ion Batteries

Cited by 37 publications

References 43 publications

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

Titanium-based potassium-ion battery positive electrode with extraordinarily high redox potential

A 4.8 V Reversible Li2CoPO4F/Graphite Battery Enabled by Concentrated Electrolytes and Optimized Cell Design

Tuning the Crystal Structure of A2CoPO4F (A = Li, Na) Fluoride‐Phosphates: A New Layered Polymorph of LiNaCoPO4F

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Crystal Structure and Li-Ion Transport in Li₂CoPO₄F High-Voltage Cathode Material for Li-Ion Batteries

A 4.8 V Reversible Li₂CoPO₄F/Graphite Battery Enabled by Concentrated Electrolytes and Optimized Cell Design

Tuning the Crystal Structure of A₂CoPO₄F (A = Li, Na) Fluoride‐Phosphates: A New Layered Polymorph of LiNaCoPO₄F