Browsing by Author "Li, B"

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    A colossal barocaloric effect induced by the creation of a high-pressure phase
    (Royal Society of Chemistry (RSC), 2023-01-13) Zhang, Z; Jiang, X; Hattori, T; Xu, X; Li, M; Yu, CY; Zhang, Z; Yu, DH; Mole, RA; Yano, SI; Chen, J; He, LH; Wang, CW; Wang, H; Li, B; Zhang, ZD
    As a promising environment-friendly alternative to current vapor-compression refrigeration, solid-state refrigeration based on the barocaloric effect has been attracting worldwide attention. Generally, both phases in which a barocaloric effect occurs are present at ambient pressure. Here, instead, we demonstrate that KPF6 exhibits a colossal barocaloric effect due to the creation of a high-pressure rhombohedral phase. The phase diagram is constructed based on pressure-dependent calorimetric, Raman scattering, and neutron diffraction measurements. The present study is expected to provide an alternative routine to colossal barocaloric effects through the creation of a high-pressure phase. © Royal Society of Chemistry 2024.
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    Constructing “Li-rich Ni-rich” oxide cathodes for high-energy-density Li-ion batteries
    (Royal Society of Chemistry, 2023-01-26) Li, B; Rousse, G; Zhang, L; Avdeev, M; Deschamps, M; Abakumov, AM; Tarascon, JM
    The current exploration of high-energy-density cathode materials for Li-ion batteries is mainly concentrated on either so-called “Li-rich” or “Ni-rich” oxides. However, both are suffering from formidable practical challenges. Here, we combine these two concepts to obtain “Li-rich Ni-rich” oxides in pursuit of more practical high-energy-density cathodes. As a proof of concept, we synthesized an array of Li1+yNi(3−5y)/3Mo2y/3O2 oxides, whose structures were identified to be the coexistence of LiNiO2-rich and Li4MoO5-rich domains with the aid of XRD, TEM, and NMR techniques. Such an intergrowth structure of 5–20 nm size enables excellent mechanical and structural reversibility for the layered rock-salt LiNiO2-rich domain upon cycling thanks to the robust cubic rock-salt Li4MoO5-rich domain enabling an “epitaxial stabilization” effect. As a result, we achieved high capacities (>220 mA h g−1) with Ni contents as low as 80%; the Li1.09Ni0.85Mo0.06O2 member (y = 0.09) shows much improved cycling performances (91% capacity retention for 100 cycles at C/10) compared with pure LiNiO2. This work validates the feasibility of constructing Li-rich Ni-rich compounds in the form of intergrowing domains and hence unlocks vast possibilities for future cathode design. © The Royal Society of Chemistry
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    Giant barocaloric effects in sodium hexafluorophosphate and hexafluoroarsenate
    (AIP Publishing, 2024-07-21) Zhang, Z; Hattori, T; Song, R; Yu, DH; Mole, RA; Chen, J; He, LH; Zhang, ZD; Li, B
    Solid-state refrigeration using barocaloric materials is environmentally friendly and highly efficient, making it a subject of global interest over the past decade. Here, we report giant barocaloric effects in sodium hexafluorophosphate (NaPF6) and sodium hexafluoroarsenate (NaAsF6) that both undergo a cubic-to-rhombohedral phase transition near room temperature. We have determined that the low-temperature phase structure of NaPF6 is a rhombohedral structure with space group R3¯ by neutron powder diffraction. There are three Raman active vibration modes in NaPF6 and NaAsF6, i.e., F2g, Eg, and A1g. The phase transition temperature varies with pressure at a rate of dTt/dP = 250 and 310 K GPa−1 for NaPF6 and NaAsF6. The pressure-induced entropy changes of NaPF6 and NaAsF6 are determined to be around 45.2 and 35.6 J kg−1 K−1, respectively. The saturation driving pressure is about 40 MPa. The pressure-dependent neutron powder diffraction suggests that the barocaloric effects are related to the pressure-induced cubic-to-rhombohedral phase transitions. © 2024 AIP Publishing LLC.
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    Magnetic ordering in the rhombohedral α-DyGa3
    (Elsevier, 2022-05-15) Cong, MR; Wang, CW; Ren, WJ; Avdeev, M; Ling, CD; Gao, F; Li, B; Zhang, ZD
    We have succeeded in growing α-DyGa3 single crystals by the self-flux method and determined its magnetic structure by neutron powder diffraction. α-DyGa3 crystallizes in the rhombohedral SrSn3-type structure (R3̅m, #166, hR48), and the magnetic sublattice is comprised of staggering layers of triangular lattice of Dy. Magnetic ordering occurs below TN ~ 7.2 K with the magnetic propagation vector k = (1/2, 0, 1/2), results in an alternating stripe antiferromagnetic structure in the ab-plane described by the magnetic space group CC2/c (BNS #15.90, origin at (0, 0, 0)). At 3.5 K, the magnetic moment is 5.72(12) μB per Dy3+. The Dy3+ spins are lying in basal plane and perpendicular to the b-axis. © 2024 Elsevier B.V
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    Thermal batteries based on inverse barocaloric effects
    (Science Advances, 2023-02) Zhang, Z; Li, K; Lin, SC; Song, R; Yu, DH; Wang, Y; Wang, JF; Kawaguchi, S; Zhang, Z; Yu, CY; Li, XD; Chen, J; He, LH; Mole, RA; Yuan, B; Ren, QY; Qian, K; Cai, ZL; Yu, JG; Wang, MC; Zhao, CY; Tong, X; Zhang, ZD; Li, B
    To harvest and reuse low-temperature waste heat, we propose and realize an emergent concept-barocaloric thermal batteries based on the large inverse barocaloric effect of ammonium thiocyanate (NH4SCN). Thermal charging is initialized upon pressurization through an order-to-disorder phase transition, and the discharging of 43 J g-1 takes place at depressurization, which is 11 times more than the input mechanical energy. The thermodynamic equilibrium nature of the pressure-restrained heat-carrying phase guarantees stable long-duration storage. The barocaloric thermal batteries reinforced by their solid microscopic mechanism are expected to substantially advance the ability to take advantage of waste heat. Copyright © 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).
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    Two pressure cells for quasielastic and inelastic neutron scatterings
    (EDP Sciences, 2022-11-17) Yuan, B; Mole, RA; Wang, CW; Shumack, A; White, R; Li, B; Tong, X; Yu, DH
    Two clamp pressure cells for QENS and INS have been developed. One is a hybrid CuBe/NiCrAl cell which is for relative high pressure up to 2.5 GPa and another one is made from high strength aluminium alloy (mesolite NA723) with pressure up to 0.5 GPa. The sample volume is 0.3 mL and 1 mL, respectively. The pressure cells have been thoroughly calibrated and tested. In addition, the contribution to phonon density of states from the pressure cells has been evaluated. Measurements of the phonon density of states for two perfluorocarbon polymer liquids FOMBLIN oil and Fluorinert have indicated that they are suitable to serve as the low background pressure transmission media for high pressure INS experiments. The applications of the pressure cells for INS and QENS are demonstrated by studies of pressure-induced phase transition of plastic crystals. © The Authors, published by EDP Sciences, 2022. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
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    Ultrasensitive barocaloric material for room-temperature solid-state refrigeration
    (Springer Nature, 2022-04-28) Ren, QY; Qi, J; Yu, DH; Zhang, Z; Song, R; Song, WL; Yuan, B; Wang, TH; Ren, WJ; Zhang, ZD; Tong, X; Li, B
    One of the greatest obstacles to the real application of solid-state refrigeration is the huge driving fields. Here, we report a giant barocaloric effect in inorganic NH4I with reversible entropy changes of ΔSmax P0!P ∼71 J K−1 kg−1 around room temperature, associated with a structural phase transition. The phase transition temperature, Tt, varies dramatically with pressure at a rate of dTt/dP ∼0.79 K MPa−1, which leads to a very small saturation driving pressure of ΔP ∼40 MPa, an extremely large barocaloric strength of ΔSmax P0!P=ΔP∼1.78 J K−1 kg−1 MPa−1, as well as a broad temperature span of ∼41 K under 80 MPa. Comprehensive characterizations of the crystal structures and atomic dynamics by neutron scattering reveal that a strong reorientation-vibration coupling is responsible for the large pressure sensitivity of Tt. This work is expected to advance the practical application of barocaloric refrigeration. © The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License.