Structural stability in terms of the decomposition temperature in LiMn_(2)O_(4) was systematically investigated by a series of high-temperature and high-pressure experiments.LiMn_(2)O_(4) was found to have structural ...Structural stability in terms of the decomposition temperature in LiMn_(2)O_(4) was systematically investigated by a series of high-temperature and high-pressure experiments.LiMn_(2)O_(4) was found to have structural stability up to 5 GPa at room temperature.Under ambient pressure,the compound decomposed at 1300℃.The decomposition temperature decreased with increasing pressure,yielding more complex decomposed products.Below the decomposition temperature,the crystal structure of LiMn_(2)O_(4) varied with pressure.The presented results in this study offer new insights into the thermal and pressure stability of LiMn_(2)O_(4) materials as a cathode for lithium-ion batteries that can operate under extreme conditions.Therefore,these findings may serve as a useful guide for future work for improving lithium-ion batteries.展开更多
Three tungsten powder samples—one coarse grained(c-W;grain size:1μm–3μm)and two nanocrystalline(n-W;average grain sizes:10nm and 50 nm)—are investigated under nonhydrostatic compression in a diamond anvil cell in...Three tungsten powder samples—one coarse grained(c-W;grain size:1μm–3μm)and two nanocrystalline(n-W;average grain sizes:10nm and 50 nm)—are investigated under nonhydrostatic compression in a diamond anvil cell in separate experiments,and their in situ X-ray diffraction patterns are recorded.The maximum microscopic deviatoric stress in each tungsten sample,a measure of the yield strength,is determined by analyzing the diffraction line width.Over the entire pressure range,the strength of tungsten increases noticeably as the grain size is decreased from 1μm–3μmto 10 nm.The results show that the yield strength of tungsten with an average crystal size of 10nmis around 3.5 times that of the sample with a grain size of 1μm–3μm.展开更多
基金by the National Natural Science Foundation of China(Grant No.12074273)the Doctoral Research Fund of Southwest University of Science and Technology(Grant No.20zx7136).
文摘Structural stability in terms of the decomposition temperature in LiMn_(2)O_(4) was systematically investigated by a series of high-temperature and high-pressure experiments.LiMn_(2)O_(4) was found to have structural stability up to 5 GPa at room temperature.Under ambient pressure,the compound decomposed at 1300℃.The decomposition temperature decreased with increasing pressure,yielding more complex decomposed products.Below the decomposition temperature,the crystal structure of LiMn_(2)O_(4) varied with pressure.The presented results in this study offer new insights into the thermal and pressure stability of LiMn_(2)O_(4) materials as a cathode for lithium-ion batteries that can operate under extreme conditions.Therefore,these findings may serve as a useful guide for future work for improving lithium-ion batteries.
基金This study was supported by the National Key R&D Program of China(Grant No.2018YFA0305900)
文摘Three tungsten powder samples—one coarse grained(c-W;grain size:1μm–3μm)and two nanocrystalline(n-W;average grain sizes:10nm and 50 nm)—are investigated under nonhydrostatic compression in a diamond anvil cell in separate experiments,and their in situ X-ray diffraction patterns are recorded.The maximum microscopic deviatoric stress in each tungsten sample,a measure of the yield strength,is determined by analyzing the diffraction line width.Over the entire pressure range,the strength of tungsten increases noticeably as the grain size is decreased from 1μm–3μmto 10 nm.The results show that the yield strength of tungsten with an average crystal size of 10nmis around 3.5 times that of the sample with a grain size of 1μm–3μm.
