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Electrode process kinetics is a key part that determines the morphology of metal electrodeposition. However, the liquid-phase mass transfer process and its effect on lithium (Li) metal electrodeposition are still poorly understood. Herein, the effect of mass transfer on the electrodeposition behavior of Li metal is explored. Experiments and COMSOL Multiphysics simulations reveal that the enhanced mass transfer, which is induced by ultrasonic wave, can homogenize the ion flow on the surface of electrode to obtain uniform Li nucleation. Meanwhile, the rapid mass transfer of Li+ provides sufficient cations around the germinated Li to avoid preferential growth of Li in a specific direction. Based on the simultaneous regulation of nucleation and growth behavior, a smooth and compact Li deposits can be achieved, which exhibit a small polarization voltage during repeated Li plating/striping and a considerably enhanced cyclability. This work enriches the fundamental understanding of Li electrodeposition without dendrite structure and affords fresh guidance to develop dendrite-free metal anodes for metal-based batteries.

Jingjing Li,1 Jingyuan You,2 Guoping Yin,1 Jinkun Xu,1 Yuhuan Zhang,1 Xuemei Yuan,1 Qiang Chen,1 Jingying Ye1,3 1Department of Otorhinopharyngology–Head and Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, People’s Republic of China; 2Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, People’s Republic of China; 3Institute of Precision Medicine, Tsinghua University, Beijing, People’s Republic of ChinaCorrespondence: Jingying Ye, Department of Otorhinopharyngology–Head and Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Litang Road 168, Beijing, 102218, People’s Republic of China, Tel +86-13701396970, Email yejingying@mail.tsinghua.edu.cnPurpose: Accumulating evidence suggests that theta/beta ratio (TBR), an electroencephalographic (EEG) frequency band parameter, might serve as an objective marker of executive cognitive control in healthy adults. Obstructive sleep apnea (OSA) has a detrimental impact on patients’ behavior and cognitive performance while whether TBR is different in OSA population has not been reported. This study aimed to explore the difference in relative EEG spectral power and TBR during sleep between patients with severe OSA and non-OSA groups.Patients and Methods: 142 participants with in-laboratory nocturnal PSG recording were included, among which 100 participants suffered severe OSA (apnea hypopnea index, AHI > 30 events/hour; OSA group) and 42 participants had no OSA (AHI ≤ 5 events/h; control group). The fast Fourier transformation was used to compute the EEG power spectrum for total sleep duration within contiguous 30-second epochs of sleep. The demographic and polysomnographic characteristics, relative EEG spectral power and TBR of the two groups were compared.Results: It was found that the beta band power during NREM sleep and total sleep was significantly higher in the OSA group than controls (p < 0.001, p = 0.012, respectively), and the theta band power during NREM sleep and total sleep was significantly lower in the OSA group than controls (p = 0.019, p = 0.014, respectively). TBR during NREM sleep, REM sleep and total sleep was significantly lower in the OSA group compared to the control group (p < 0.001 for NREM sleep and total sleep, p = 0.015 for REM sleep). TBR was negatively correlated with AHI during NREM sleep (r=− 0.324, p < 0.001) and total sleep (r=− 0. 312, p < 0.001).Conclusion: TBR was significantly decreased in severe OSA patients compared to the controls, which was attributed to both increased beta power and decreased theta power. TBR may be a stable EEG-biomarker of OSA patients, which may accurately and reliably identify phenotype of patients.Keywords: sleep electroencephalography, spectral power, frequency band ratio, theta/beta ratio, OSA

Extra-terrestrial explorations require electrochemical energy storage devices able to operate in gravity conditions different from those of planet earth. In this context, lithium (Li)-based batteries have not been fully investigated, especially cell formation and cycling performances under supergravity (i.e., gravity > 9.8 m s−2) conditions. To shed some light on these aspects, here, we investigate the behavior of non-aqueous Li metal cells under supergravity conditions. The physicochemical and electrochemical characterizations reveal that, distinctly from earth gravity conditions, smooth and dense Li metal depositions are obtained under supergravity during Li metal deposition on a Cu substrate. Moreover, supergravity allows the formation of an inorganic-rich solid electrolyte interphase (SEI) due to the strong interactions between Li+ and salt anions, which promote significant decomposition of the anions on the negative electrode surface. Tests in full Li metal pouch cell configuration (using LiNi0.8Co0.1Mn0.1O2-based positive electrode and LiFSI-based electrolyte solution) also demonstrate the favorable effect of the supergravity in terms of deposition morphology and SEI composition and ability to carry out 200 cycles at 2 C (400 mA g−1) rate with a capacity retention of 96%., The behavior of lithium metal batteries at various gravity levels is not yet clearly understood. Here, the authors demonstrate the beneficial effect of supergravity in terms of battery performance improvement and favorable solid electrolyte interphase formation.

Designing efficient electrocatalysts with high electroconductivity, strong chemisorption, and superior catalytical efficiency to realize rapid kinetics of the lithium polysulfides (LiPSs) conversion process is crucial for practical lithium-sulfur (Li-S) battery applications. Unfortunately, most current electrocatalysts cannot maintain long-term stability due to the possible failure of catalytic sites. Herein, a novel dynamic electrocatalytic strategy with the liquid metal (i.e., gallium-tin, EGaSn) to facilitate LiPSs redox reaction is reported. The combined theoretical simulations and microstructure experiment analysis reveal that Sn atoms dynamically distributed in the liquid Ga matrix act as the main active catalytic center. Meanwhile, Ga provides a uniquely dynamic environment to maintain the long-term integrity of the catalytic system. With the participation of EGaSn, a tailor-made 2 Ah Li-S pouch cell with a specific energy density of 307.7 Wh kg