Integrating lithium metal anodes with polymer electrolytes is a promising technology for the next generation high-energy-density rechargeable batteries.As the progress is often hindered by the dendrite growth upon cyc...Integrating lithium metal anodes with polymer electrolytes is a promising technology for the next generation high-energy-density rechargeable batteries.As the progress is often hindered by the dendrite growth upon cycling,quantifying three-dimensional(3D)microstructures of dendrites in polymer electrolytes is essential to better understanding of dendrite formation for the development of mitigation strategies.Techniques for 3D quantification and visualization of dendrites,especially those with low Li contents,are rather limited.This study reports quantitative measurements of the spatial distribution of Li dendrites grown in solid polymer electrolytes using 3D tomographic neutron depth profiling(NDP)with improved spatial resolution,compositional range,and data presentation.Data reveal heterogeneous distribution of Li over length scales from tens nanometers to centimeters.While most dendrites grow from the plating toward the stripping electrode with dwindling Li quantities,dendrites apparently grown from the Li-stripping electrode are also observed.The discovery is only possibly due to the unique combination of the high specificity and high sensitivity of the neutron activation analysis of Li isotope.展开更多
The energy spreading of recorded ions is influenced by straggling,geometrical acceptance angles and detector energy resolution effects in neutron depth profiling(NDP)and a symmetric Gaussian function model was customa...The energy spreading of recorded ions is influenced by straggling,geometrical acceptance angles and detector energy resolution effects in neutron depth profiling(NDP)and a symmetric Gaussian function model was customarily applied before.In addition,the spectra of mono-energetic alpha particles show a well known asymmetric shape as well when measured by silicon detectors.This article presents a physical model predicting the observed energy spectrum of a sample ion with target nuclides in prearranged depths.It is expressed as the convolution of a Gaussian function with a left-hand double-exponential function.Experiment showed that the predicted ions spectrum derived from the asymmetric model matches the observed energy spectrum.Therefore,the model can be applied to produce matrix for inversion of NDP spectrum.展开更多
The hydrogen mean force from experimental neutron Compton profiles is derived using deep inelastic neutron scattering on amorphous and polycrystalline ice. The formalism of mean force is extended to probe its sensitiv...The hydrogen mean force from experimental neutron Compton profiles is derived using deep inelastic neutron scattering on amorphous and polycrystalline ice. The formalism of mean force is extended to probe its sensitivity to anharmonicity in the hydrogen-nucleus effective potential. The shape of the mean force for amorphous and polycrystalline ice is primarily determined by the anisotropy of the underlying quasi-harmonic effective potential. The data from amorphous ice show an additional curvature reflecting the more pronounced anharmonicity of the effective potential with respect to that of ice Ih.展开更多
基金supported by the Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515110398)National Natural Science Foundation of China(Grant No.12105197)H.Wang acknowledges the support of the National Institute of Standards and Technology through award 70NANB12H238.
文摘Integrating lithium metal anodes with polymer electrolytes is a promising technology for the next generation high-energy-density rechargeable batteries.As the progress is often hindered by the dendrite growth upon cycling,quantifying three-dimensional(3D)microstructures of dendrites in polymer electrolytes is essential to better understanding of dendrite formation for the development of mitigation strategies.Techniques for 3D quantification and visualization of dendrites,especially those with low Li contents,are rather limited.This study reports quantitative measurements of the spatial distribution of Li dendrites grown in solid polymer electrolytes using 3D tomographic neutron depth profiling(NDP)with improved spatial resolution,compositional range,and data presentation.Data reveal heterogeneous distribution of Li over length scales from tens nanometers to centimeters.While most dendrites grow from the plating toward the stripping electrode with dwindling Li quantities,dendrites apparently grown from the Li-stripping electrode are also observed.The discovery is only possibly due to the unique combination of the high specificity and high sensitivity of the neutron activation analysis of Li isotope.
文摘The energy spreading of recorded ions is influenced by straggling,geometrical acceptance angles and detector energy resolution effects in neutron depth profiling(NDP)and a symmetric Gaussian function model was customarily applied before.In addition,the spectra of mono-energetic alpha particles show a well known asymmetric shape as well when measured by silicon detectors.This article presents a physical model predicting the observed energy spectrum of a sample ion with target nuclides in prearranged depths.It is expressed as the convolution of a Gaussian function with a left-hand double-exponential function.Experiment showed that the predicted ions spectrum derived from the asymmetric model matches the observed energy spectrum.Therefore,the model can be applied to produce matrix for inversion of NDP spectrum.
文摘The hydrogen mean force from experimental neutron Compton profiles is derived using deep inelastic neutron scattering on amorphous and polycrystalline ice. The formalism of mean force is extended to probe its sensitivity to anharmonicity in the hydrogen-nucleus effective potential. The shape of the mean force for amorphous and polycrystalline ice is primarily determined by the anisotropy of the underlying quasi-harmonic effective potential. The data from amorphous ice show an additional curvature reflecting the more pronounced anharmonicity of the effective potential with respect to that of ice Ih.
