Microstructural evolution and performance of hydrogen storage and electrochemistry of Co-added La 0.75 Mg 0.25 Ni 3.5−x Co x (x = 0, 0.2, 0.5 at%) alloys

Lv, Wei; Shi, Yufan; Deng, Wanpeng; Yuan, Jianguang; Yan, Youhua; Wu, Ying

doi:10.1016/j.pnsc.2017.07.004

Cited by 15 publications

(3 citation statements)

References 47 publications

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“…This process is easier for Pr 5 Co 19 -type structure than Ce 5 Co 19 -type structure. Compared with the results about Co element substitution in LaNi 3.5 and LaNi 3.8 alloys,21,30 Our experiments showed different results in (La,Mg)Ni 3.8 alloy. This means Mg element has important role in the formation of super lattice structure.…”

contrasting

confidence: 43%

“…However, Lv et al found that the increase of Co leads to the decrease of super lattice phase in La(Ni,Co) 3.5 alloys, and Zhong et al also reported that the substitution of Co for Ni frustrated the formation of A 5 B 19 phase in the La(Ni,Co) 3.8 alloys with lower maximum discharge capacity (C max = 261.4mAh/g). 21,30 Above all, it is believed that Mg and Co elements have important influence on the formation of A 5 B 19 -type super lattice structures. In the previous work, our group found that small substitution of Co for Ni could promote the formation of A 5 B 19 -type phase in the La 4 MgNi 19-x Co x (x = 0∼2) alloys, in which the highest A 5 B 19 -type phase abundance is 72.8wt% (x = 2).…”

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confidence: 99%

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Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Wei

Cai

Zhou

et al. 2019

J. Electrochem. Soc.

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A series of (La 0.85 Mg 0.15 ) 5 Ni 19-x Co x (x = 3.25∼11.25) alloys were melted by using intermediate alloys in induction melting furnace, and then annealed at 1173K for 8h. The super lattice structure and electrochemical properties of the alloys were systematically investigated. It is found that the x value of 5.25 or 7.25 can help to form super lattice (La, Mg) 5 Ni 19 phase (>92wt%), and when x exceeds 7.25, there appears (La,Mg) 2 Ni 7 phase in alloys. Corresponding to the change of phase structure, the electrochemical properties of the alloys showed the same trend, for example, the alloy with x = 5.25 have good maximum discharge capacity (C max = 394.44mAh/g), capacity retention rate (S 100 = 82.36%) and high-rate dischargeability (HRD 900 = 92.27%). However, further increase of x obviously decreases those properties. The further testing results illustrated that a higher Co content in the alloy can improve its anti-pulverization and anti-corrosion capacity, but decrease the exchange current density and the diffusion coefficient of hydrogen in alloys. This leads to a higher cyclic life and a lower HRD of the alloys with a higher Co concentration.

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confidence: 43%

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confidence: 99%

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Wei

Cai

Zhou

et al. 2019

J. Electrochem. Soc.

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“…In contrast, [ A 2 B 4 ] subunits can store a higher amount of hydrogen, but their stability is poor, which results in the collapse of the crystal structure and, consequently, a fast capacity decay of the alloy . In addition, the interaction between the subunits affects the structural stability of the alloy as well: the volume expansion and contraction between the [ AB 5 ] and [ A 2 B 4 ] subunits during the hydrogenation and dehydrogenation process can be desynchronized, which causes lattice strain inside the crystal structure, leading to the pulverization and loss of discharge capacity of the alloy. − It is also demonstrated that structures with a high [ AB 5 ]:[ A 2 B 4 ] subunit ratio (i.e., a large number of C subunits between the L layers) show better cycling stability when used as electrode materials, , confirming the key role of [ AB 5 ] subunits in improving the cyclability.…”

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confidence: 99%

Quantification of Stacking Faults in ANi_y (A = Rare Earth or Mg, y = 3.5 and 3.67) Hydrogen Storage Materials

et al. 2022

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AB y (A = rare earth or Mg, B = transition metal, 2 < y < 5)-based alloys with varying stoichiometries are being studied in recent years for hydrogen storage and as negative electrode materials for Ni-MH batteries. Their structure can be described as the periodic stacking along the c crystallographic axis of two fundamental layers, [AB 5 ] and [A 2 B 4 ] (labeled as C and L, respectively), and often exhibits stacking defects (loss of periodicity locally). The layer type and the stacking sequence play an important role in the hydrogenation and electrochemical properties. The volume mismatch between the two subunits [AB 5 ] and [A 2 B 4 ] is the main cause of the multiplateau behavior and the irreversibility of the binary RNi y (R = rare earths) compounds. The multielement compounds with [A 2 B 4 ] and [AB 5 ] subunits that are similar in size tend to show better stability. In this paper, the defect structure of four different materials exhibiting different types of stacking faults is analyzed by utilizing a combination of high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and X-ray diffraction (XRD) data. The analysis of the X-ray diffraction patterns is done using the FAULTS software, which allows one to determine the nature of the stacking faults and to quantify them. The quantitative description of the different case studies has brought unprecedented insight into rationalizing and correlating the differences between the different structural subunits and hydrogen storage properties.

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Effect of Y, Al Co-Doping on Hydrogen Storage Properties of La–Mg–Ni-Based Alloys

Wu,

Xie,

et al. 2024

Acta Metall. Sin. (Engl. Lett.)

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Microstructural evolution and performance of hydrogen storage and electrochemistry of Co-added La 0.75 Mg 0.25 Ni 3.5−x Co x (x = 0, 0.2, 0.5 at%) alloys

Cited by 15 publications

References 47 publications

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Quantification of Stacking Faults in ANi_y (A = Rare Earth or Mg, y = 3.5 and 3.67) Hydrogen Storage Materials

Effect of Y, Al Co-Doping on Hydrogen Storage Properties of La–Mg–Ni-Based Alloys

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Microstructural evolution and performance of hydrogen storage and electrochemistry of Co-added La 0.75 Mg 0.25 Ni 3.5−x Co x (x = 0, 0.2, 0.5 at%) alloys

Cited by 15 publications

References 47 publications

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)5 (Ni,Co)19 Hydrogen Storage Alloys

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)5 (Ni,Co)19 Hydrogen Storage Alloys

Quantification of Stacking Faults in ANiy (A = Rare Earth or Mg, y = 3.5 and 3.67) Hydrogen Storage Materials

Effect of Y, Al Co-Doping on Hydrogen Storage Properties of La–Mg–Ni-Based Alloys

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Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Effect of Higher Cobalt on Super Lattice Structure and Electrochemical Properties of (La,Mg)₅ (Ni,Co)₁₉ Hydrogen Storage Alloys

Quantification of Stacking Faults in ANi_y (A = Rare Earth or Mg, y = 3.5 and 3.67) Hydrogen Storage Materials