Phase transformation and cycling characteristics of a Ce2Ni7-type single-phase La0.78Mg0.22Ni3.45 metal hydride alloy

Zhang, Lu; Li, Yuan; Zhao, Xiuchen; Liu, Jingjing; Ke, Dandan; Du, Wenkai; Yang, Shuqin; Han, Shumin

doi:10.1039/c5ta02554k

Cited by 34 publications

(5 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Combining with the result of Rietveld refinement, in the temperature range of 1123-1223 K, the abundance of AB 5 type phase keeps decreasing as well as the abundance of A 5 B 19 type phase while the abundance of A 2 B 7 type phase keeps increasing. In this process, it is supposed that the new formed A 2 B 7 type phase is generated by AB 5 and A 5 B 19 type phases via peritectic reactions at 1123-1223 K. 26,27 In Fig. 3c of the alloys annealed at 1248 K for 24 h, the areas of AB 5 and A 5 B 19 type phases keep diminishing and this is consistent with the result of Rietveld refinement.…”

Section: Methodssupporting

confidence: 78%

“…According to previous reports and the results of XPS test, the hexagonal flake is the hydroxide of Mg. 26 With the cycle number increases to 100, the amount of the La(OH) 3 and Mg(OH) 2 keeps increasing. The surface of the alloy is covered by a layer of the white spicule.…”

Section: Study Of Capacity Decay Mechanismmentioning

confidence: 98%

“…7 also give a support on this conclusion that the hexagonal flakes of the Mg hydroxides are only found after 50 and 100 cycles. 26 So it is believed that the oxidation reactions of the Mg mainly occur in the early stage. While for the La element, the oxidation of La is going on for the entire charge/discharge process.…”

Section: Study Of Capacity Decay Mechanismmentioning

confidence: 99%

See 2 more Smart Citations

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Zhang¹,

Wang²,

Cao³

et al. 2017

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

Single Gd 2 Co 7 -type phase La 0.65 Gd 0.10 Mg 0.25 Ni 3.50 alloy is prepared with induction melting followed by annealing treatment. Rietveld refinements show that the as-cast alloy consists of CaCu 5 -type phase, Gd 2 Co 7 -type phase and Ce 5 Co 19 -type phase. At temperature of 1123-1248 K, the CaCu 5 -type and Ce 5 Co 19 -type phases transform into Gd 2 Co 7 -type phase via peritectic reactions. As annealed at 1248 K for 36 h, the CaCu 5 -type and Ce 5 Co 19 -type phases totally transform into Gd 2 Co 7 -type phase and the alloy shows a single phase structure. The increasing abundance of Gd 2 Co 7 -type phase makes a significant improvement on the discharge capacity and the Gd 2 Co 7 -type single phase alloy shows a superior discharge capacity of 386 mAh g −1 . Moreover, the Gd 2 Co 7 -type single phase alloy exhibits preferable capacity retention, which is up to 88.4% at the 160th cycles. The pulverization of the single phase alloy mainly occurs at earlier stage and the average particle size is not significantly reduced after 50 charge/discharge cycles. It is found that the oxidation of Mg mainly occurs at an early stage, while the oxidation of La happens in the whole process of charge/discharge cycling. Moreover, the oxidation of La gets aggravated after 100 cycles as the hydroxides of La is observed growing from nanoscale (<100 nm) needles (100th cycles) to micrometer-size (>2 μm) rods (150th cycles).

show abstract

Section: Methodssupporting

confidence: 78%

Section: Study Of Capacity Decay Mechanismmentioning

confidence: 98%

See 1 more Smart Citation

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Zhang¹,

Wang²,

Cao³

et al. 2017

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is supposed that the Gd 2 Co 7 -type phase transforms into Ce 2 Ni 7 phase at a higher temperature as the Gd 2 Co 7 phase is low temperature stable phase. 22 When the annealing temperature gets higher than the thermal stability temperature of Gd 2 Co 7 phase, the transformation would occur. As the temperature increased to 1323 K, the Gd 2 Co 7 -type completely transforms into Ce 2 Ni 7 phase and the crystal structure of the alloy (#5) changes into single-phase Ce 2 Ni 7 -type.…”

Section: Resultsmentioning

confidence: 99%

Self-Discharge Characteristic of La_0.60Nd_0.15Mg_0.25Ni_3.50 Alloy with Single-Phase Ce₂Ni₇-Type Super-Stacking Structure

Zhang

Guo

Liu

et al. 2018

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

Self-discharge performance is one of the key indexes of nickel-metal hydride batteries. In this work, single-phase Ce 2 Ni 7 -type La-Nd-Mg-Ni-based alloy with great application potential in long-term storage Ni/MH batteries are prepared by step-wise annealing. The as-cast alloy contains CaCu 5 -, Gd 2 Co 7 -and Ce 5 Co 19 -type phases. After annealed at 1248 K, CaCu 5 -and Ce 5 Co 19 -type phases disappear and a single-phase Gd 2 Co 7 -type structure is obtained. With the temperature increase, Gd 2 Co 7 -type structure begins to transform into Ce 2 Ni 7 -type structure. As annealed at 1323 K, the alloy shows a Ce 2 Ni 7 -type single-phase structure. The C 60 (discharge capacity at 60 mA g −1 ) of Ce 2 Ni 7 -type electrode reaches 405 mAh g −1 , and the C 1900 is even high to 210 mAh g −1 .The Ce 2 Ni 7 -type electrode also shows superior self-discharge properties and the charge retention rate for 1 d (CRT 1d ) is 96.5%. Moreover after 150 cycles, the CRT 1d is even high to 97.7% and CRT 7d is 81.5%. While those of the as-cast electrodes are only 79% and 36%, respectively. Electrochemical pressure-composition isotherms show that Ce 2 Ni 7 -type electrode has relatively lower hydrogen desorption plateau pressure, indicating more stable hydride and less reversible self-discharge. After 150 cycles, the plateau pressure gets even lower. Moreover Ce 2 Ni 7 -type electrode possesses smaller corrosion current density, indicating minor oxidation/corrosion degree.

show abstract

“…In the last two decades, various approaches have been proposed to improve the electrochemical properties of HSAs, such as composition optimization13, surface modification1415, preparation techniques modification16, processing methods optimization17 etc. The surface modification has been demonstrated as an efficient approach to enhance the HRD performance of HSAs.…”

mentioning

confidence: 99%

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

Yang

Wang

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world’s dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials—hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g−1, which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

show abstract

Phase transformation and cycling characteristics of a Ce₂Ni₇-type single-phase La_0.78Mg_0.22Ni_3.45 metal hydride alloy

Abstract: A Ce2Ni7-type single-phase La0.78Mg0.22Ni3.45 alloy has been prepared by zoning annealing of the as-cast sample.

Cited by 34 publications

References 24 publications

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Self-Discharge Characteristic of La_0.60Nd_0.15Mg_0.25Ni_3.50 Alloy with Single-Phase Ce₂Ni₇-Type Super-Stacking Structure

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

Contact Info

Product

Resources

About

Phase transformation and cycling characteristics of a Ce2Ni7-type single-phase La0.78Mg0.22Ni3.45 metal hydride alloy

Abstract: A Ce2Ni7-type single-phase La0.78Mg0.22Ni3.45 alloy has been prepared by zoning annealing of the as-cast sample.

Cited by 34 publications

References 24 publications

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd2Co7-type Superlattice Structure La0.65Gd0.10Mg0.25Ni3.50Metal Hydride Alloy

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd2Co7-type Superlattice Structure La0.65Gd0.10Mg0.25Ni3.50Metal Hydride Alloy

Self-Discharge Characteristic of La0.60Nd0.15Mg0.25Ni3.50 Alloy with Single-Phase Ce2Ni7-Type Super-Stacking Structure

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

Contact Info

Product

Resources

About

Phase transformation and cycling characteristics of a Ce₂Ni₇-type single-phase La_0.78Mg_0.22Ni_3.45 metal hydride alloy

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Preparation, Electrochemical Properties and Capacity Degradation Mechanism of Gd₂Co₇-type Superlattice Structure La_0.65Gd_0.10Mg_0.25Ni_3.50Metal Hydride Alloy

Self-Discharge Characteristic of La_0.60Nd_0.15Mg_0.25Ni_3.50 Alloy with Single-Phase Ce₂Ni₇-Type Super-Stacking Structure