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3286 KiB

Open AccessArticle

Sol-Gel Synthesized Antimony Anodes for Sodium-Ion Batteries: Identifying Key Parameters for Optimization

by Nicholas E. Drewett, Juan Luis Gómez-Cámer, Begoña Acebedo, Montserrat Galceran and Teófilo Rojo

Batteries 2017, 3(3), 20; https://doi.org/10.3390/batteries3030020 - 30 Jun 2017

Cited by 6 | Viewed by 7373

The potentially high gravimetric capacities of intermetallic anodes, coupled with the low cost and readily available materials used in sodium-ion batteries, has generated interest in antimony—an anode capable of alloying with sodium. However, presently there are few synthetic routes to antimony particles for [...] Read more.

The potentially high gravimetric capacities of intermetallic anodes, coupled with the low cost and readily available materials used in sodium-ion batteries, has generated interest in antimony—an anode capable of alloying with sodium. However, presently there are few synthetic routes to antimony particles for use in sodium-ion batteries. One pot, sol-gel synthetic routes from readily available, chloride-free precursors have been developed. The resulting products have been characterized and, from this data, several key parameters’ optimization have been identified and are presented here. Finally, using this information, some initial optimization has been carried out, which resulted in minor improvements to the physical and electrochemical properties of the resulting product. Full article

(This article belongs to the Special Issue Physical Properties of Sodium-Ion Battery Materials)

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1671 KiB

Open AccessArticle

Influence of Using Metallic Na on the Interfacial and Transport Properties of Na-Ion Batteries

by Maider Zarrabeitia, Miguel Ángel Muñoz-Márquez, Francesco Nobili, Teófilo Rojo and Montse Casas-Cabanas

Batteries 2017, 3(2), 16; https://doi.org/10.3390/batteries3020016 - 10 May 2017

Cited by 17 | Viewed by 8591

Abstract

Na₂Ti₃O₇ is a promising negative electrode for rechargeable Na-ion batteries; however, its good properties in terms of insertion voltage and specific capacity are hampered by the poor capacity retention reported in the past. The interfacial and ionic/electronic properties [...] Read more.

Na₂Ti₃O₇ is a promising negative electrode for rechargeable Na-ion batteries; however, its good properties in terms of insertion voltage and specific capacity are hampered by the poor capacity retention reported in the past. The interfacial and ionic/electronic properties are key factors to understanding the electrochemical performance of Na₂Ti₃O₇. Therefore, its study is of utmost importance. In addition, although rather unexplored, the use of metallic Na in half-cell studies is another important issue due to the fact that side-reactions will be induced when metallic Na is in contact with the electrolyte. Hence, in this work the interfacial and transport properties of full Na-ion cells have been investigated and compared with half-cells upon electrochemical cycling by means of X-ray photoelectron spectroscopy (conventional XPS and Auger parameter analysis) and electrochemical impedance spectroscopy. The half-cell has been assembled with C-coated Na₂Ti₃O₇ against metallic Na whilst the full-cell uses C-coated Na₂Ti₃O₇ as negative electrode and NaFePO₄ as positive electrode, delivering 112 Wh/kg_{anode+cathode} in the 2nd cycle. When comparing both types of cells, it has been found that the interfacial properties, the OCV (open circuit voltage) and the electrode–-electrolyte interphase behavior are more stable in the full-cell than in the half-cell. The electronic transition from insulator to conductor previously observed in a half-cell for Na₂Ti₃O₇ has also been detected in the full-cell impedance analysis. Full article

(This article belongs to the Special Issue Physical Properties of Sodium-Ion Battery Materials)

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662 KiB

Open AccessArticle

Low Voltage Charge/Discharge Behavior of Manganese Hexacyanoferrate

by Takayuki Shibata, Masamitsu Takachi and Yutaka Moritomo

Batteries 2017, 3(1), 7; https://doi.org/10.3390/batteries3010007 - 10 Mar 2017

Cited by 9 | Viewed by 7951

Abstract

Recently, Prussian blue analogues (PBAs) have been reported to exhibit a low voltage charge/discharge behavior with high capacity (300–545 mAh/g) in lithium-ion secondary batteries (LIBs) [...] Full article

(This article belongs to the Special Issue Physical Properties of Sodium-Ion Battery Materials)

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550 KiB

Open AccessArticle

Domain Size of Phase-Separated Na_xCoO₂ as Investigated by X-Ray Microdiffraction

by Hideharu Niwa, Takayuki Shibata, Yasuhiko Imai, Shigeru Kimura and Yutaka Moritomo

Batteries 2017, 3(1), 5; https://doi.org/10.3390/batteries3010005 - 02 Mar 2017

Cited by 3 | Viewed by 7959

Abstract

O3-NaCoO

_{2}

is a promising cathode material for sodium ion secondary batteries (SIBs). Na

_{x}

CoO

_{2}

shows phase separation (PS) into the O3 and O

^{'}

3 phases in the Na concentration range of 0.89

⩽ x ⩽

0.99. In order to [...] Read more.

O3-NaCoO

_{2}

is a promising cathode material for sodium ion secondary batteries (SIBs). Na

_{x}

CoO

_{2}

shows phase separation (PS) into the O3 and O

^{'}

3 phases in the Na concentration range of 0.89

⩽ x ⩽

0.99. In order to estimate the domain size (r) in the two-phase region, we performed X-ray microdiffraction (XRMD) of thin films of Na

_{x}

CoO

_{2}

at x = 0.97 and ∼1. We found that r (≈400 nm) of the O

^{'}

3 domain is comparable to the particle size d (=331 ± 87 nm) in the as-grown O3-NaCoO

_{2}

film. This observation suggests that individual particles of Na

_{x}

CoO

_{2}

are single phase to minimize the strain at the O3–O

^{'}

3 phase boundary. Full article

(This article belongs to the Special Issue Physical Properties of Sodium-Ion Battery Materials)

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