Single-crystalline layered oxide materials for lithium-ion batteries are featured by their excellent capacity retention over their polycrystalline counterparts,making them sought-after cathode candidates.Their capacit...Single-crystalline layered oxide materials for lithium-ion batteries are featured by their excellent capacity retention over their polycrystalline counterparts,making them sought-after cathode candidates.Their capacity degradation,however,becomes more severe under high-voltage cycling,hindering many high-energy applications.It has long been speculated that the interplay among composition heterogeneity,lattice deformation,and redox stratification could be a driving force for the performance decay.The underlying mechanism,however,is not well-understood.In this study,we use X-ray microscopy to systematically examine single-crystalline NMC particles at the mesoscale.This technique allows us to capture detailed signals of diffraction,spectroscopy,and fluorescence,offering spatially resolved multimodal insights.Focusing on early high-voltage charging cycles,we uncover heterogeneities in valence states and lattice structures that are inherent rather than caused by electrochemical abuse.These heterogeneities are closely associated with compositional variations within individual particles.Our findings provide useful insights for refining material synthesis and processing for enhanced battery longevity and efficiency.展开更多
基金This research used resources 3-ID Hard x-ray nano probe and 18-ID full field x-ray imaging of the National Synchrotron Light Source IIa U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No.DE-SC0012704+2 种基金Stanford Synchrotron Radiation Lightsource of the SLAC National Accelerator Laboratory is supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Contract No.DE-AC02-76SF00515The work at the Central Universities of Central South University was sponsored by the National Natural Science Foundation of China(52172264)Fundamental Research Funds from Central Universities of Central South University.We would like to extend our gratitude to Yinjia Zhang and Liangjin Gong from Ke Du's group at Central South University for their technical support and useful discussions.
文摘Single-crystalline layered oxide materials for lithium-ion batteries are featured by their excellent capacity retention over their polycrystalline counterparts,making them sought-after cathode candidates.Their capacity degradation,however,becomes more severe under high-voltage cycling,hindering many high-energy applications.It has long been speculated that the interplay among composition heterogeneity,lattice deformation,and redox stratification could be a driving force for the performance decay.The underlying mechanism,however,is not well-understood.In this study,we use X-ray microscopy to systematically examine single-crystalline NMC particles at the mesoscale.This technique allows us to capture detailed signals of diffraction,spectroscopy,and fluorescence,offering spatially resolved multimodal insights.Focusing on early high-voltage charging cycles,we uncover heterogeneities in valence states and lattice structures that are inherent rather than caused by electrochemical abuse.These heterogeneities are closely associated with compositional variations within individual particles.Our findings provide useful insights for refining material synthesis and processing for enhanced battery longevity and efficiency.
