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Because 3D batteries comprise solid polymer electrolytes (SPE) confined to high surface area porous scaffolds, the interplay between polymer confinement and interfacial interactions on total ionic conductivity must be understood. This paper investigates contributions to the structure-conductivity relationship in poly(ethylene oxide) (PEO)–lithium bis(trifluorosulfonylimide) (LiTFSI) complexes confined to microporous nickel scaffolds. For bulk and confined conditions, PEO crystallinity decreases as the salt concentration (Li+:EO (r) = 0.0.125, 0.0167, 0.025, 0.05) increases. For pure PEO and all r values except 0.05, PEO crystallinity under confinement is lower than in the bulk, whereas glass transition temperature remains statistically invariant. At 298 K (semicrystalline), total ionic conductivity under confinement is higher than in the bulk at r = 0.0167, but remains invariant at r = 0.05; however, at 350 K (amorphous), total ionic conductivity is higher than in the bulk for both salt concentrations. Time–of–flight secondary ion mass spectrometry indicates selective migration of ions towards the polymer–scaffold interface. In summary, for the 3D structure studied, polymer crystallinity, interfacial segregation, and tortuosity play an important role in determining total ionic conductivity and, ultimately, the emergence of 3D SPEs as energy storage materials. 

Abstract It is essential to understand the nanoscale structure and chemistry of energy storage materials due to their profound impact on battery performance. However, it is often challenging to characterize them at high resolution, as they are often fundamentally altered by sample preparation methods. Here, we use the cryogenic lift-out technique in a plasma-focused ion beam (PFIB)/scanning electron microscope (SEM) to prepare air-sensitive lithium metal to understand ion-beam damage during sample preparation. Through the use of cryogenic transmission electron microscopy, we find that lithium was not damaged by ion-beam milling although lithium oxide shells form in the PFIB/SEM chamber, as evidenced by diffraction information from cryogenic lift-out lithium lamellae prepared at two different thicknesses (130 and 225 nm). Cryogenic energy loss spectroscopy further confirms that lithium was oxidized during the process of sample preparation. The Ellingham diagram suggests that lithium can react with trace oxygen gas in the FIB/SEM chamber at cryogenic temperatures, and we show that liquid oxygen does not contribute to the oxidation of lithium process. Our results suggest the importance of understanding how cryogenic lift-out sample preparation has an impact on the high-resolution characterization of reactive battery materials. 

An environmentally responsible synthesis of Na_2/3[Ni_1/3Mn_2/3]O₂(NNMO) enabled by direct conversion of metallic Ni powder, releasing only O₂and H₂O as byproducts. The resulting NNMO exhibits excellent cycling performance as a Na-ion battery cathode. 

One step pore diffusion mechanism of lithium ion transport in the solid electrolyte interphase (SEI) layer with discrete inorganic components enables the fast lithium conduction without slow solid state diffusion process.