Rational Lithium Salt Molecule Tuning for Fast Charging/Discharging Lithium Metal Battery.

The electrolytes for lithium metal batteries (LMBs) are plagued by a low Li+ transference number (T+) of conventional lithium salts and inability to form a stable solid electrolyte interphase (SEI). Here, we synthesized a self-folded lithium salt, lithium 2-[2-(2-methoxy ethoxy)ethoxy]ethanesulfonyl(trifluoromethanesulfonyl) imide (LiETFSI), and comparatively studied with its structure analogue, lithium 1,1,1-trifluoro-N-[2-[2-(2-methoxyethoxy)ethoxy)]ethyl]methanesulfonamide (LiFEA). The special anion chemistry imparts the following new characteristics: i) In both LiFEA and LiETFSI, the ethylene oxide moiety efficiently captures Li+, resulting in a self-folded structure and high T+ around 0.8. ii) For LiFEA, a Li-N bond (2.069 Å) is revealed by single crystal X-ray diffraction, indicating that the FEA anion possesses a high donor number (DN) and thus an intensive interphase "self-cleaning" function for an ultra-thin and compact SEI. iii) Starting from LiFEA, an electron-withdrawing sulfone group is introduced near the N atom. The distance of Li-N is tuned from 2.069 Šin LiFEA to 4.367 Šin LiETFSI. This alteration enhances ionic separation, achieves a more balanced DN, and tunes the self-cleaning intensity for a reinforced SEI. Consequently, the fast charging/discharging capability of LMBs is progressively improved. This rationally tuned anion chemistry reshapes the interactions among Li+, anions, and solvents, presenting new prospects for advanced LMBs.

Fluorinated Carbamate-Based Electrolyte Enables Anion-Dominated Solid Electrolyte Interphase for Highly Reversible Li Metal Anode.

Li metal is regarded as the most promising battery anode to boost energy density. However, being faced with the hostile compatibility between the Li anode and traditional carbonate electrolyte, its large-scale industrialization has been in a distressing circumstance due to severe dendrite growth caused by unsatisfying solid electrolyte interphase (SEI). With this regard, accurate control over the composition of the SEI is urgently desired to tackle the electrochemical and mechanical instability at the electrolyte/anode interface. Herein, we report a rationally designed fluorinated carbamate-based electrolyte employing LiNO3 as one of the main salts to induce the preferable anion decomposition to achieve a homogeneous and inorganic (LiF, Li3N, Li2O)-rich SEI. Thus, this electrolyte achieves a high Coulombic efficiency of 99% of the Li metal anode, a stable cycling over 1000 h for Li|Li symmetric cells, more than 100 cycles in 40-µm-thin Li|high-loading-NCM811 full batteries, and >50 cycles in Cu|LiFePO4 pouch cells, which is a promising electrolyte for highly reversible Li metal batteries.

A multi-granularity convolutional neural network model with temporal information and attention mechanism for efficient diabetes medical cost prediction.

As the cost of diabetes treatment continues to grow, it is critical to accurately predict the medical costs of diabetes. Most medical cost studies based on convolutional neural networks (CNNs) ignore the importance of multi-granularity information of medical concepts and time interval characteristics of patients' multiple visit sequences, which reflect the frequency of patient visits and the severity of the disease. Therefore, this paper proposes a new end-to-end deep neural network structure, MST-CNN, for medical cost prediction. The MST-CNN model improves the representation quality of medical concepts by constructing a multi-granularity embedding model of medical concepts and incorporates a time interval vector to accurately measure the frequency of patient visits and form an accurate representation of medical events. Moreover, the MST-CNN model integrates a channel attention mechanism to adaptively adjust the channel weights to focus on significant medical features. The MST-CNN model systematically addresses the problem of deep learning models for temporal data representation. A case study and three comparative experiments are conducted using data collected from Pingjiang County. Through experiments, the methods used in the proposed model are analyzed, and the super contribution of the model performance is demonstrated.

Novel Urea-Based Molecule Functioning as a Solid Electrolyte Interphase Enabler and LiPF6 Decomposition Inhibitor for Fast-Charging Lithium Metal Batteries.

The practical application of lithium metal batteries is impeded by the growth of dendrites and decomposition of electrolytes especially at high temperature in normal carbonate-based electrolytes. Herein, a novel urea-based molecule, 1,3-dimethyl-2-imidazolidinone (DMI), with a high donor number is proposed, which exhibits an extraordinary solubility of LiNO3 of over 5 M. As a result, a sufficient amount of LiNO3 is readily introduced into the carbonate electrolytes with DMI as an additive, and an average coulombic efficiency of 99.1% for lithium plating/stripping is achieved due to a stable solid electrolyte interphase (SEI) rich in inorganic-rich lithium salts. The Li||Li symmetric cell achieves a stable operation for over 2500 h at 0.5 mA cm-2 and 1 mAh cm-2, and a granular shape of deposited Li metal is still preserved even at a high current density of 10 mA cm-2. Besides, the decomposition of LiPF6 is inhibited benefiting from its enhanced dissociation after the addition of DMI/LiNO3 and DMI's function as a PF5 scavenger. Consequently, the Li||LiFePO4 cell succeeds to achieve an excellent capacity retention of 95.6% after 2200 cycles at a high rate of 5C, and a stable operation is realized at a high temperature of 60 °C even under harsh conditions (45 µm ultrathin Li and ∼1.5 mAh cm-2 LiFePO4). This work enriches the solvents and additives pool for stable and high-performance lithium metal batteries and will shed light on future developments of advanced battery electrolytes.

Rationally Designed Fluorinated Amide Additive Enables the Stable Operation of Lithium Metal Batteries by Regulating the Interfacial Chemistry.

A fluorinated amide molecule with two functional segments, namely, an amide group with a high donor number to bind lithium ions and a fluorine chain to expel carbonate solvents and mediate the formation of LiF, was designed to regulate the interfacial chemistry. As expected, the additive preferably appears in the first solvation sheath of lithium ions and is electrochemically reduced on the anode, and thus an inorganic-rich solid electrolyte interphase is generated. The morphology of deposited lithium metal evolves from brittle dendrites into a granular shape. Consequently, the Li||LiFePO4 cell shows an excellent capacity retention of 92.7% at a high rate of 5 C after 800 cycles. Besides, the Li||LiNi0.8Co0.1Mn0.1O2 cell succeeds to maintain 98.1% of the initial capacity after 100 cycles at 1 C. Our designing of N,N-diethyl- 2,3,3,3-tetrafluoropropionamide (denoted as DETFP) highlights the importance of a "high donor number" and may shed light on the design principles of electrolytes for high performance batteries.

The anxiolytic effects of valtrate in rats involves changes of corticosterone levels.

Valtrate is a principle compound isolated from Valeriana jatamansi Jones, which is a Traditional Chinese Medicine used to treat various mood disorders. The aim of the present study was to investigate the anxiolytic effects of valtrate in rats. The animals were orally administered valtrate (5, 10, and 20 g/kg daily) for 10 days and exposed to open field test (OFT) and elevated plus-maze (EPM). Then the corticosterone levels in the rat serum were measured by enzyme-linked immunosorbent assay (ELISA). The valtrate (10 mg/kg, p.o.) exhibited the anxiolytic effect in rats by increasing the time and entry percentage into the open arms in the EPM and the number of central entries in the OFT. Valtrate (10 mg/kg, p.o.) significantly reduced the corticosterone level in the rat serum. Taken together, these results suggest that the valtrate has anxiolytic activity in behavioral models that might be mediated via the function of hypothalamus-pituitary-adrenal axis.

[Mass spectrum characterization of five valepotriates by electrospray ionization tandem mass spectrometry].

OBJECTIVE: To discuss mass spectrum characterization of five valepotriates including 'monoene' type (didrovaltrate), 'diene' type (valtrate, acevaltrate) and 'four-olefinic' type (baldrinal and homobaldrinal) by electrospray ionization tandem mass spectrometry (ESI-MS(n)). METHOD: This study was carried out on the basis of electrospray ionization tandem mass spectrometric method and analysis of multistage fragments. RESULT: The fragmentation patterns and structural assignment of 'monoene' type, 'diene' type and 'four-olefinic' type valepotriates in ESI-MSn under positive mode were summarized. CONCLUSION: The compounds have a strong pyrolysis rules and it can provide reference date for valepotriates in rapid structural identification, quantitative analysis and pharmacokinetic study.