Article
Nanoscience & Nanotechnology
D. Merida, I. Unzueta, V. Sanchez-Alarcos, V. Recarte, J. I. Perez-Landazabal, J. A. Garcia, F. Plazaola
Summary: Vacancy mediated diffusion is the main mechanism controlling the ordering of substitutional alloys, particularly in Ni-Mn-Ga shape memory alloys. This study adapts a phenomenological model to quantify the evolution of vacancy concentration during the ordering process in three different Ni-Mn-Ga alloys. The results demonstrate that out of equilibrium vacancies are responsible for the ordering process and determine the governing parameters.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Multidisciplinary
Kei Kubota, Takuya Asari, Shinichi Komaba
Summary: It has been found that dual substitution of Ti-IV for Mn-IV and Zn-II for Ni-II in P2-Na-2/3[Ni1/3Mn2/3]O-2 can disturb the Na+-vacancy ordering, resulting in almost non-step voltage curves and high reversible capacity with maintained crystalline structure. Synchrotron X-ray, neutron, and electron diffraction measurements reveal that the dual-substitution uniquely promotes in-plane Ni-II-Mn-IV ordering, which differs from the disordered mixing in conventional multiple metal substitution.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Dong Luo, Xiaokai Ding, Xiaodong Hao, Huixian Xie, Jiaxiang Cui, Peizhi Liu, Xiaohua Yang, Zuhao Zhang, Junjie Guo, Shuhui Sun, Zhan Lin
Summary: The study successfully alleviated the voltage decay and capacity fading issues of LLO cathodes by constructing Co-free LLO microspheres with Ni/Mn and Al dual concentration-gradients, providing a new pathway for their practical application in the near future.
ACS ENERGY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Y. -h. Chan, Hong-Chen Jiang, Y. -c. Chen
Summary: We studied the ground-state phase diagram of the spin-1/2 J1-J2 XY model on a square lattice with first-neighbor J1 and second-neighbor J2 antiferromagnetic interactions using iDMRG and DMRG approaches. We found a plaquette valence bond phase in the intermediate region 0.50 J2/J1 < 0.54, a Neel magnetic ordered phase at J2/J1 < 0.50, and a stripy magnetic ordered phase at J2/J1 > 0.54. The plaquette valence bond phase is characterized by finite dimer orders in both the horizontal and vertical directions. Contrary to the spin-1/2 J1-J2 Heisenberg model, no numerical evidence for a quantum spin liquid phase was found in the J1-J2 XY model.
Article
Materials Science, Multidisciplinary
Fei Sun, Goro Miyamoto, Yikun Liu, Yuichiro Hayasaka, Tadashi Furuhara
Summary: This study investigates the phase separation and ordering phenomena during aging of Fe-35Ni-35Mn medium-entropy alloy using advanced characterization techniques. The results reveal that phase separation is induced by Mn clustering in the early stage of aging. A statistical thermodynamic model suggests that nucleation of the L1(0) phase should precede phase separation at 500 degrees C, while phase separation is possible in a disordered state at 400 degrees C and ordering further enhances it.
Article
Engineering, Environmental
Sangho Yoon, Gwanghyeon Choi, Jaewoon Lee, Juncheol Hwang, Duho Kim
Summary: In this study, a method is proposed to mitigate the formation of micro-cracks in LiNiO2-based cathode materials in lithium-ion batteries by controlling the structure of transition metal oxides and doping with Ti. It is found that LiNiTiO2 exhibits lower lattice strain during charging compared to LiNiO2, indicating reduced mechanical failures. Ti doping induces a uniform bond network that connects the NiO6 octahedral network, and the difference in Li-O bond populations between the two materials is attributed to the chemical stiffness. This study provides insights into the mechanism of the Ti-doping effect and offers a strategy to enhance the durability of high-energy-density LIBs.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Jimmy Jiahong Kuo, Stephen Dongmin Kang, William C. Chueh
Summary: The resistance in lithium-ion battery positive electrodes is mainly determined by the bulk resistance of the active material and the network resistance of the carbon additive, while the impact of contact resistance is often underestimated. The study found that contact resistance dominates the overall resistance when the length scale is smaller than millimeters.
ADVANCED ENERGY MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Masari Watanabe, Nobuyuki Kurita, Hidekazu Tanaka, Wataru Ueno, Kazuki Matsui, Takayuki Goto, Masato Hagihala
Summary: We report the magnetic properties of the double perovskites SrLaCuSbO6 and SrLaCuNbO6. Both compounds show characteristic behavior of square lattice Heisenberg antiferromagnets with S = 1/2. Neutron powder diffraction measurements reveal different spin structures in the two compounds, with SLCSO exhibiting a Neel antiferromagnetic structure and SLCNO exhibiting a columnar antiferromagnetic structure. The dominant interactions in SLCSO and SLCNO are nearest-neighbor and next-nearest-neighbor interactions, respectively. Additionally, the measured ordered moments are significantly smaller than those predicted by linear spin wave theory, indicating the effect of bond randomness caused by site disorder.
Article
Chemistry, Physical
Haotian Xie, Ying Tang, Yang Yang, Ning Zhang, Xiaolong Gu, Huaicheng Xiang
Summary: In this study, the intrinsic factors affecting the microwave dielectric properties of Ga-based garnet Ca3B1.5Ga3.5O12 were investigated using bond valence and P-V-L methods. The relationship between lattice-induced strain effect and dielectric polarization was elucidated. The measured permittivity was inconsistent with the calculated values due to the different ionic polarizability of Nb5+ and Ta5+.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Environmental
Shuyun Yao, Rui Zhao, Shiyu Wang, Yixiang Zhou, Ruochen Liu, Lingyuan Hu, Anqi Zhang, Ru Yang, Xia Liu, Zhenzhen Fu, Dewei Wang, Zhiyu Yang, Yi-Ming Yan
Summary: This study introduces a structure distortion strategy via Ni doping in MnO2 to enhance its Na+ storage performance, demonstrating improved cycling stability and ionic transport kinetics. The Ni-MnO2 material achieved high specific capacity, excellent rate performance, and promising cycling life, showcasing potential for application in energy storage devices.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Wang Wang, Ershuai Liu, Youcheng Hu, Li Jiao, Praveen Kolla, Yucheng Liu, Meihua Tang, Jin Luo, Qiang Sun, Shengli Chen, Qingying Jia, Sanjeev Mukerjee
Summary: This study investigates the nature of the active sites in a CoMn2O4 catalyst, revealing the superior activity of Co-Mn spinel oxides is related to the Mn2+/Mn3+ redox transition, which is significantly affected by the operating potential window. This irreversible activity decay is proposed to be caused by the irreversible change of the Jahn-Teller distortion during the Mn2+/Mn3+ transition.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Energy & Fuels
Faiza Iram, Ghulam M. Mustafa, Ghulam Ali, Haseeb Ahmad, Shahid M. Ramay, Zaffar Iqbal, Shahid Atiq
Summary: In this study, the electrochemical performance of CuO was improved by doping it with different transition metals. It was found that Ni-doped CuO showed the highest specific capacitance and cyclic stability, along with the best electrical conductivity and highly porous morphology. Therefore, Ni-doped CuO can be considered as the most desirable electrode material for pseudocapacitors.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Materials Science, Multidisciplinary
Pratyay Ghosh, Tobias Mueller, Ronny Thomale
Summary: The study presents the exact dimer ground state of a quantum antiferromagnet on the maple-leaf lattice, where a coupling anisotropy for one of the three inequivalent nearest-neighbor bonds is sufficient to stabilize the dimer state.
Article
Materials Science, Multidisciplinary
G. Subias, J. Blasco, V. Cuartero, S. Lafuerza, L. Simonelli, G. Gorni, M. Castro, J. Garcia
Summary: We investigated the temperature dependence of Mn local structure in A-site ordered RBaMn2O6 perovskites and their disordered counterparts R0.5Ba0.5MnO3 using XES and XAS. The results show that the MnO6 octahedron in LaBaMn2O6 remains regular at all temperatures, while a local distortion develops with decreasing R ionic radius in the ordered samples NdBaMn2O6, SmBaMn2O6, and YBaMn2O6. Charge segregation between nonequivalent Mn sites is confirmed in the polar phase of Sm and Y ordered samples. The study suggests a displacive mechanism for the charge-localization and polar transitions in Nd and Sm ordered samples, while a combination of displacive and order-disorder contributions is revealed for YBaMn2O6.
Article
Chemistry, Multidisciplinary
Yongseok Lee, Hyunyoung Park, Min-kyung Cho, Jinho Ahn, Wonseok Ko, Jungmin Kang, Yoo Jung Choi, Hyungsub Kim, Inchul Park, Won-Hee Ryu, Jihyun Hong, Jongsoon Kim
Summary: A novel cathode material, Li1.8Mg0.3Mn0.9O3, has been proposed to enhance the capacity and energy density of Li2MnO3 by partially substituting Li+ and Mn4+ with inactive Mg2+. The Mg substitution effectively suppresses Mn migration and mitigates oxygen release, resulting in improved power-capability and cycle performance.
ADVANCED FUNCTIONAL MATERIALS
(2022)
