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- Brant, William, et al.
(författare)
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Comparative analysis of ex-situ and operando X-ray diffraction experiments for lithium insertion materials
- 2016
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 302, s. 126-134
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Tidskriftsartikel (refereegranskat)abstract
- AbstractA comparative study of ex-situ and operando X-ray diffraction techniques using the fast lithium ion conductor Li0.18Sr0.66Ti0.5Nb0.5O3 is presented. Ex-situ analysis of synchrotron X-ray diffraction data suggests that a single phase material exists for all discharges to as low as 0.422 V. For samples discharged to 1 V or lower, i.e. with higher lithium content, it is possible to determine the lithium position from the X-ray data. However, operando X-ray diffraction from a coin cell reveals that a kinetically driven two phase region occurs during battery cycling below 1 V. Through monitoring the change in unit cell dimension during electrochemical cycling the dynamics of lithium insertion are explored. A reduction in the rate of unit cell expansion of 22(2)% part way through the first discharge and 13(1)% during the second discharge is observed. This reduction may be caused by a drop in lithium diffusion into the bulk material for higher lithium contents. A more significant change is a jump in the unit cell expansion by 60(2)% once the lithium content exceeds one lithium ion per vacant site. It is suggested that this jump is caused by damping of octahedral rotations, thus establishing a link between lithium content and octahedral rotations.Graphical abstract
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| 3. |
- Brant, William R., et al.
(författare)
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Rapid Lithium Insertion and Location of Mobile Lithium in the Defect Perovskite Li0.18Sr0.66Ti0.5Nb0.5O3
- 2012
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Ingår i: ChemPhysChem. - : Wiley-Blackwell. - 1439-4235 .- 1439-7641. ; 13:9, s. 2293-2296
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Tidskriftsartikel (refereegranskat)abstract
- Fast and fancy: Lithium that was originally disordered within the structure of the perovskite Li0.18Sr0.66Ti0.5Nb0.5O3 can be induced into ordering within the yellow region of the unit cell by low temperatures and treatment with n-butyl-lithium. The fast kinetics of lithium insertion, in connection with a color change, make this nontoxic, air-stable material a suitable candidate for use in electrochromic systems or lithium-storage batteries.
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| 4. |
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| 5. |
- Lai, Qiwen, et al.
(författare)
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Hydrogen Storage Materials for Mobile and Stationary Applications : Current State of the Art
- 2015
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 8:17, s. 2789-2825
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Tidskriftsartikel (refereegranskat)abstract
- One of the limitations to the widespread use of hydrogen as an energy carrier is its storage in a safe and compact form. Herein, recent developments in effective high-capacity hydrogen storage materials are reviewed, with a special emphasis on light compounds, including those based on organic porous structures, boron, nitrogen, and aluminum. These elements and their related compounds hold the promise of high, reversible, and practical hydrogen storage capacity for mobile applications, including vehicles and portable power equipment, but also for the large scale and distributed storage of energy for stationary applications. Current understanding of the fundamental principles that govern the interaction of hydrogen with these light compounds is summarized, as well as basic strategies to meet practical targets of hydrogen uptake and release. The limitation of these strategies and current understanding is also discussed and new directions proposed.
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| 10. |
- Whittle, Thomas A., et al.
(författare)
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Tailoring phase transition temperatures in perovskites via A-site vacancy generation
- 2017
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 46:22, s. 7253-7260
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Tidskriftsartikel (refereegranskat)abstract
- The structures across the Sr0.8Ti0.6-xZrxNb0.4O3, 0 <= x <= 0.6, defect perovskite series were investigated using complementary synchrotron X-ray and neutron powder diffraction data. The locations of second order compositional and temperature dependent phase transitions between the high symmetry cubic Pm (3) over barm phase and the lower symmetry tetragonal I4/mcm phase were determined. Deviation of the oxygen x coordinate from the high symmetry value and the B-O-B bond angle from 180 degrees as well as the tetragonal strain squared were each found to be suitable order parameters to monitor the transitions. Tolerance factor calculations confirmed that these A-site deficient perovskites retain a higher symmetry to a lower value than their fully occupied counterparts. Therefore, adjusting vacancy concentrations can be employed as a general strategy to design compounds with specifically tailored phase transition temperatures.
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