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A combination of cryogenic electron microscopy and cryogenic focused ion beam enabled the characterization of the interface between Li metal and lithium phosphorous oxynitride, one of the well-known interfaces to exhibit exemplary electrochemical stability with a lithium metal anode. The probed structural and chemical information leads to a more comprehensive understanding of the underlying cause for the interfacial stability and its formation mechanism.

N95 decontamination protocols and KN95 respirators have been described as solutions to a lack of personal protective equipment. However, there are a few material science studies that characterize the charge distribution and physical changes accompanying disinfection treatments, particularly heating. Here, we report the filtration efficiency, dipole charge density, and fiber integrity of N95 and KN95 respirators before and after various decontamination methods. We found that the filter layers in N95 and KN95 respirators maintained their fiber integrity without any deformations during disinfection. The filter layers of N95 respirators were 8-fold thicker and had 2-fold higher dipole charge density than that of KN95 respirators. Emergency Use Authorization (EUA)-approved KN95 respirators showed filtration efficiencies as high as N95 respirators. Interestingly, although there was a significant drop in the dipole charge in both respirators during decontamination, there was no remarkable decrease in the filtration efficiencies due to mechanical filtration. Cotton and polyester face masks had a lower filtration efficiency and lower dipole charge. In conclusion, a loss of electrostatic charge does not directly correlate to the decreased performance of either respirator.

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Lithium phosphorus oxynitride (LiPON) is an amorphous solid-state lithium ion conductor displaying exemplary cyclability against lithium metal anodes.T here is no definitive explanation for this stability due to the limited understanding of the structure of LiPON.H erein, we provide astructural model of RF-sputtered LiPON.Information about the short-range structure results from 1D and 2D solid-state NMR experiments.T hese results are compared with first principles chemical shielding calculations of LiP -O/N crystals and ab initio molecular dynamics-generated amorphous LiP-ON models to unequivocally identify the glassy structure as primarily isolated phosphate monomers with Ni ncorporated in both apical and as bridging sites in phosphate dimers. Structural results suggest LiPON'ss tability is ar esult of its glassy character.Free-standing LiPON films are produced that exhibit ah igh degree of flexibility,h ighlighting the unique mechanical properties of glassy materials.