Fast Li-Ion Conduction in Spinel-Structured Solids.

Spinel-structured solids were studied to understand if fast Li+ ion conduction can be achieved with Li occupying multiple crystallographic sites of the structure to form a "Li-stuffed" spinel, and if the concept is applicable to prepare a high mixed electronic-ionic conductive, electrochemically active solid solution of the Li+ stuffed spinel with spinel-structured Li-ion battery electrodes. This could enable a single-phase fully solid electrode eliminating multi-phase interface incompatibility and impedance commonly observed in multi-phase solid electrolyte-cathode composites. Materials of composition Li1.25M(III)0.25TiO4, M(III) = Cr or Al were prepared through solid-state methods. The room-temperature bulk Li+-ion conductivity is 1.63 × 10-4 S cm-1 for the composition Li1.25Cr0.25Ti1.5O4. Addition of Li3BO3 (LBO) increases ionic and electronic conductivity reaching a bulk Li+ ion conductivity averaging 6.8 × 10-4 S cm-1, a total Li-ion conductivity averaging 4.2 × 10-4 S cm-1, and electronic conductivity averaging 3.8 × 10-4 S cm-1 for the composition Li1.25Cr0.25Ti1.5O4 with 1 wt. % LBO. An electrochemically active solid solution of Li1.25Cr0.25Mn1.5O4 and LiNi0.5Mn1.5O4 was prepared. This work proves that Li-stuffed spinels can achieve fast Li-ion conduction and that the concept is potentially useful to enable a single-phase fully solid electrode without interphase impedance.

Curriculum Innovations: A Podcast-Based Neurologic Emergency Flipped Classroom Curriculum for Neurology Residents.

Introduction: Education on the management of neurologic emergencies is vital for neurology residents, and effective educational methods are needed. This study aims to implement and evaluate the impact of a podcast-based flipped classroom curriculum in neurologic emergencies. "Flipped classroom" instructional methods have been used in GME and informed by experiential learning theory. Curriculum Objectives: The objectives of this curriculum were to (1) compare the clinical phenomena discussed in the neurologic emergencies podcast(s) with your own clinical experience; (2) discuss the pitfalls in the management of the neurologic emergencies discussed in the podcast(s); and (3) develop a management plan for the neurologic emergencies discussed in the podcast(s). Methods: At 10 neurology residency programs, we implemented a 3-session flipped classroom curriculum covering topics in acute stroke, movement disorder emergencies, and status epilepticus. Each session consisted of a Neurology® podcast followed by content discussion with a clinical expert. Assessment of the curriculum included presession and postsession surveys focused on learners' confidence and attitudes toward podcast-based education. Results: Our data sample consisted of survey responses from residents, with response volumes ranging from 29-111 across all surveys. Podcasts are already highly used by neurology residents in their self-directed education. Confidence increased among learners in the management of movement disorder emergencies (18% confident before vs 79% confident after, p < 0.001) and status epilepticus (72% confident before vs 91% confident after, p = 0.014) among those who completed the curriculum. A change in confidence in acute stroke management was not found (p = 0.15). Podcasts were consistently preferred over lectures and reading-based instructional methods while less preferred compared with simulation-based learning and case-based discussion with faculty. The podcast-based curriculum studied here showed high levels of enjoyment and perceived utility. Conclusions: We present a 3-part curriculum to help build learners' familiarity and confidence in 3 neurologic emergency categories. The educational impact is established in Level 1 of the Kirkpatrick paradigm. Future studies can explore a higher-level impact of this curriculum. Evolution in neurology education is shifting increasingly toward immediately accessible information via digital media. This curriculum can be useful to neurology educators who need to be increasingly agile and facile with multiple educational techniques to meet learners' needs.

Does stapedotomy improve high frequency conductive hearing?

OBJECTIVES: Stapedotomy is performed to address conductive hearing deficits. While hearing thresholds reliably improve at low frequencies (LF), conductive outcomes at high frequencies (HF) are less reliable and have not been well described. Herein, we evaluate post-operative HF air-bone gap (ABG) changes and measure HF air conduction (AC) thresholds changes as a function of frequency. METHODS: Retrospective review of patients who underwent primary stapedotomy with incus wire piston prosthesis between January 2016 and May 2020. Pre- and postoperative audiograms were evaluated. LF ABG was calculated as the mean ABG of thresholds at 250, 500, and 1000 Hz. HF ABG was calculated at 4 kHz. RESULTS: Forty-six cases met criteria. Mean age at surgery was 54.0 ± 11.7 years. The LF mean preoperative ABG was 36.9 ± 11.0 dB and postoperatively this significantly reduced to 9.35 ± 6.76 dB, (P < .001). The HF mean preoperative ABG was 31.1 ± 14.4 dB and postoperatively, this also significantly reduced to 14.5 ± 12.3 dB, (P < .001). The magnitude of LF ABG closure was over 1.5 times the magnitude of HF ABG closure (P < .001). The gain in AC decreased with increasing frequency (P < .001). CONCLUSION: Hearing improvement following stapedotomy is greater at low than high frequencies. Postoperative air bone gaps persist at 4 kHz. Further biomechanical and histopathologic work is necessary to localize postoperative high frequency conductive hearing deficits and improve stapedotomy hearing outcomes. LEVEL OF EVIDENCE: 4, retrospective study.

Enabling "lithium-free" manufacturing of pure lithium metal solid-state batteries through in situ plating.

The coupling of solid-state electrolytes with a Li-metal anode and state-of-the-art (SOA) cathode materials is a promising path to develop inherently safe batteries with high energy density (>1000 Wh L-1). However, integrating metallic Li with solid-electrolytes using scalable processes is not only challenging, but also adds extraneous volume since SOA cathodes are fully lithiated. Here we show the potential for "Li-free" battery manufacturing using the Li7La3Zr2O12 (LLZO) electrolyte. We demonstrate that Li-metal anodes >20 µm can be electroplated onto a current collector in situ without LLZO degradation and we propose a model to relate electrochemical and nucleation behavior. A full cell consisting of in situ formed Li, LLZO, and NCA is demonstrated, which exhibits stable cycling over 50 cycles with high Coulombic efficiencies. These findings demonstrate the viability of "Li-free" configurations using LLZO which may guide the design and manufacturing of high energy density solid-state batteries.