Browsing by Author "Shaw, Christopher"
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Item Open Access Advances in test and measurement of the interface adhesion and bond strengths in coating-substrate systems, emphasising blister and bulk techniques(Elsevier, 2019-03-11) Chen, Xiaomei; Shaw, Christopher; Gelman, Len; Grattan, Kenneth T. V.In this paper, recent advances in the minimum-destructive testing of the adhesion of coating-substrate systems are reviewed, focusing on key techniques such as micro- and nano-scale levels of indentation, scratching, laser-induced wave shock, as well as the blister and buckle approach. Along with adhesion failure tests, the latest and most extensive applications of the adhesion test methods in nano-, micro- and bulk-coating technology and the associated techniques to determine the minimum damage defects left on the coatings are discussed and their use reviewed.Item Open Access Electrical and mechanical characterisation of poly(ethylene)oxide-polysulfone blend for composite structural lithium batteries(MDPI, 2023-06-05) Gucci, Francesco; Grasso, Marzio; Russo, Stefano; Leighton, Glenn J. T.; Shaw, Christopher; Brighton, JamesIn this work, a blend of PEO, polysulfone (PSF), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSi) was prepared at different PEO–PSf weight ratios (70-30, 80-20, and 90-10) and ethylene oxide to lithium (EO/Li) ratios (16/1, 20/1, 30/1, and 50/1). The samples were characterised using FT-IR, DSC, and XRD. Young’s modulus and tensile strength were evaluated at room temperature with micro-tensile testing. The ionic conductivity was measured between 5 °C and 45 °C through electrochemical impedance spectroscopy (EIS). The samples with a ratio of PEO and PSf equal to 70-30 and EO/Li ratio equal to 16/1 have the highest conductivity (1.91 × 10−4 S/cm) at 25 °C, while the PEO–PSf 80-20 EO/Li = 50/1 have the highest averaged Young’s modulus of about 1.5 GPa at 25 °C. The configuration with a good balance between electrical and mechanical properties is the PEO–PSf 70-30 EO/Li = 30/1, which has a conductivity of 1.17 × 10−4 S/cm and a Young’s modulus of 800 MPa, both measured at 25 °C. It was also found that increasing the EO/Li ratio to 16/1 dramatically affects the mechanical properties of the samples with them showing extreme embrittlement.Item Open Access Enhanced energy storage performance of (1-x)(BCT-BMT)-xBFO lead-free relaxor ferroelectric ceramics in a broad temperature range(Elsevier, 2019-03-03) Xu, Mengxing; Peng, Biaolin; Zhu, Jinian; Liu, Laijun; Sun, Wenhong; Leighton, Glenn J. T.; Shaw, Christopher; Luo, Nengneng; Zhang, QiRelaxor ferroelectrics with high energy storage performances are very attractive for modern applications in electronic devices and systems. Here, it is demonstrated that large energy densities (0.52e0.58 J/cm3) simultaneously with high efficiencies (76è2%) and thermal stabilities (the minimum variation of efficiency < 4% from 323 K to 423 K at x ¼ 0.04) have been achieved in the (1-x)(BCT-BMT)-xBFO lead-free relaxor ferroelectric ceramics prepared using a conventional solid-state reaction method. Large dielectric breakdown strengths and great relaxor dispersion around the dielectric peaks are responsible for the excellent energy storage performances. The energy storage performances of as-prepared ceramics at high BFO doping amount (x ¼ 0.06 and 0.07) were deteriorated seriously due to low dielectric breakdown strengths. However, they could be greatly improved when aged, since the operable electric field was significantly enhanced from 10 kV/cm of as-prepared samples to 100 kV/cm of aged samples due to the reduced concentration of oxygen vacancies during the aging process. The excellent energy storage performances may make them attractive materials for applications in modern energy storage systems in a broad temperature range.Item Open Access High-performance La-doped BCZT thin film capacitors on LaNiO3/Pt composite bottom electrodes with ultra-high efficiency and high thermal stability(Elsevier, 2019-03-13) He, Shangkai; Peng, Biaolin; Leighton, Glenn J. T.; Shaw, Christopher; Wang, Ningzhang; Sun, Wenhong; Liu, Laijun; Zhang, QiDielectric capacitors possessing large energy storage density, high efficiency and high thermal stability simultaneously are very attractive in modern electronic devices to be operated in harsh environment. Here, it is demonstrated that large energy storage density (W ∼ 15.5 J/cm3), ultra-high efficiency (η ∼93.7%) and high thermal stability (the variation of both W from 20 °C to 260 °C and η from 20 °C to 140 °C is less than 5%) have been simultaneously achieved in the La-doped (Ba0.904Ca0.096)0.9775+xLa0.015(Zr0.136Ti0.864)O3 (x = 0.0075) lead-free relaxor ferroelectric thin film capacitors deposited on LaNiO3/Pt composite bottom electrodes by using a sol-gel method. The good energy storage property of the thin film capacitors at x = 0.0075 is mainly ascribed to the diversity of the structure of the nano-clusters around the three-phases coexisting component point (Ba0.904Ca0.096)(Zr0.136Ti0.864)O3 where cubic, tetragonal and rhombohedral phases coexisted, as well as the ultra-high quality of thin film due to the utilization of the LaNiO3/Pt composite bottom electrode, making it a promising candidate for dielectric capacitors working in harsh environments.Item Open Access In-situ tuning of catalytic activity by thermoelectric effect for ethylene oxidation(American Chemical Society, 2018-09-20) Achour, Abdenour; Liu, Jian; Peng, Ping; Shaw, Christopher; Huang, ZhaorongThermoelectric material BiCuSeO used as a support and promoter for catalytic ethylene oxidation is reported here. The catalytic activity on the continuous and non-continuous catalyst Pt supported on BiCuSeO was observed to be promoted in-situ by a thermoelectric Seebeck voltage generated by the temperature gradient across the material. It is also shown this thermoelectric promotion of catalysis enabled the thermoelectric material BiCuSeO itself to be highly catalytic active for ethylene oxidation. A good linear relationship between the logarithm of the reaction rate and the thermoelectric Seebeck voltage was observed. This thermoelectric promotion of catalysis is attributed to the change of work function of the catalyst surface, accompanied by a charge transfer from the bulk to the surface due to the thermoelectric effect.Item Open Access Phase-transition induced giant negative electrocaloric effect in a lead-free relaxor ferroelectric thin film(Royal Society of Chemistry, 2019-05-02) Peng, Biaolin; Zhang, Qi; Gang, Bai; Leighton, Glenn J. T.; Shaw, Christopher; Milne, Steven J.; Zou, Bingsuo; Sun, Wenhong; Huang, Haitao; Wang, ZhonglinFerroelectric/antiferroelectric thin/thick films with large positive or negative electrocaloric (EC) effects could be very useful in designing commercial refrigeration devices. Here, a giant negative EC effect (maximum ΔT ∼ −42.5 K with ΔS ∼ −29.3 J K−1 kg−1) comparable to the best positive EC effects reported so far is demonstrated for 0.5(Ba0.8Ca0.2)TiO3–0.5Bi(Mg0.5Ti0.5)O3 (BCT–BMT) lead-free relaxor ferroelectric thin films prepared on Pt(111)/TiOx/SiO2/Si substrates using a sol–gel method. An electric-field induced structural phase transition (nanoscale tetragonal and orthorhombic to rhombohedral) along the out-of-plane [111] direction plays a very key role in developing the giant negative EC effect. This breakthrough will pave the way for practical applications of next-generation refrigeration devices with high cooling efficiency in one cycle by ingeniously utilizing and combining both the giant negative and positive EC effects. Moreover, a large energy density of 51.7 J cm−3 with a high power density of 1.15 × 1010 W kg−1 at room temperature is also achieved in the thin film, indicating that it is also an attractive multifunctional material for energy storage.Item Open Access Tailoring the electrocaloric effect of Pb0.78Ba0.2La0.02ZrO3 relaxor thin film by GaN substrates(Royal Society of Chemistry, 2019-11-06) Peng, Biaolin; Jiang, Jintao; Tang, Silin; Zhang, Miaomiao; Liu, Laijun; Zou, Bingsuo; Leighton, Glenn J. T.; Shaw, Christopher; Luo, Nengneng; Zhang, Qi; Sun, WenhongThe electrocaloric (EC) effect in ferroelectric/antiferroelectric thin films has been widely investigated due to its potential applications in solid state cooling devices. It is demonstrated that the EC effect of the Pb0.78Ba0.2La0.02ZrO3 (PBLZ) relaxor thin films prepared by using a sol–gel method strongly depends on the substrates. The maximum ΔT of PBLZ thin films deposited on Pt(111)/TiOx/SiO2/Si(100) (Pt), LaNiO3/Pt(111)/TiOx/SiO2/Si(100) (LaNiO3/Pt), LaNiO3/n-type GaN (LaNiO3/n-GaN) and LaNiO3/p-type GaN (LaNiO3/p-GaN) substrates is ∼13.08 K, 16.46 K, 18.70 K, and 14.64 K, respectively. Moreover, negative EC effects in a broad temperature range (∼340 K to 440 K) could be obtained in the thin films deposited on LaNiO3/n-GaN and LaNiO3/p-GaN substrates, which is ascribed to higher proportions of orthorhombic antiferroelectric phase to rhombohedral ferroelectric phase induced by the GaN substrates. These results indicate that tailoring the EC effects by changing the substrates could provide a new strategy in designing an EC cooling device with high cooling efficiency.Item Open Access Thermal strain induced large electrocaloric effect of relaxor thin film on LaNiO3/Pt composite electrode with the coexistence of nanoscale antiferroelectric and ferroelectric phases in a broad temperature range(Elsevier, 2018-03-08) Peng, Biaolin; Zhang, Qi; Lyu, Yinong; Liu, Laijun; Lou, Xiaojie; Shaw, Christopher; Huang, Haitao; Wang, ZhonglinFerroelectric/antiferroelectric thin/thick films with large electrocaloric (EC) effect in a broad operational temperature range are very attractive in solid-state cooling devices. We demonstrated that a large positive electrocaloric (EC) effect (maximum ΔT ~ 20.7 K) in a broad temperature range (~ 110 K) was realized in Pb0.97La0.02(Zr0.65Sn0.3Ti0.05)O3 (PLZST) relaxor antiferroelectric (AFE) thin film prepared using a sol-gel method. The large positive EC effect may be ascribed to the in-plane residual thermal tensile stress during the layer-by-layer annealing process, and the high-quality film structure owing to the utilization of the LaNiO3/Pt composite bottom electrode. The broad EC temperature range may be ascribed to the great dielectric relaxor dispersion around the dielectric peak because of the coexistence of nanoscale multiple FE and AFE phases. Moreover, a large pyroelectric energy density (6.10 Jcm−3) was harvested by using an Olsen cycle, which is much larger than those (usually less than 10− Jcm−3) obtained by using direct thermal-electrical, Stirling and Carnot cycles, etc. These breakthroughs enable the PLZST thin film an attractive multifunctional material for applications in modern solid-state cooling and energy harvesting.