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The low‐concentration electrolyte possesses the benefits of desirable wettability, low viscosity, and low cost. However, the mechanism of its poor electrochemical performance is not clear. Herein, the properties of interfacial films on the surface of LiFePO4 (LFP) cathode material formed by electrolytes with different concentrations are compared by interfacial component analysis. It is shown that moderate content of lithium fluoride increases the length of Li+–ethylene carbonate bond from 1.676 to 1.824 Å through lithium bond and then decreases the desolvation activity energy of Li+ ion, which effectively promotes the desolvation process of Li+ ion at the interface of LFP/electrolyte, and finally ensures the perfect performance of the battery. That is, the fundamental cause for the undesirable electrochemical performances of the low‐concentration electrolyte is the low content of LiF components in the interface film rather than the low ionic conductivity of the electrolyte itself. This indicates the direction of optimizing the electrochemical performance of low‐concentration electrolytes. [ABSTRACT FROM AUTHOR]

Aims: Cardiac autonomic neuropathy (CAN) is a serious complication of diabetes and is associated with adipokines. The C1q tumor necrosis factor‐related protein 9 (CTRP9) is a newly discovered adipokine. This study aimed to evaluate the association of serum CTRP9 levels with the prevalence and severity of CAN in patients with type 2 diabetes mellitus. Materials and Methods: We enrolled 262 patients (aged ≥18 years) with type 2 diabetes mellitus into this study. Standard cardiovascular autonomic reflex tests (CARTs) were used to assess CAN and patients were divided into three groups accordingly: a non‐CAN group, an early CAN group, and a definite CAN group. Serum CTRP9 levels were measured by enzyme‐linked immunosorbent assay, and the tertiles were calculated. Results: Serum CTRP9 levels decreased significantly in the early CAN and definite CAN groups (P < 0.05). The percentage of definite CAN was the highest at the minimum tertile of serum CTRP9 level (T1; P < 0.05). Additionally, serum CTRP9 levels were negatively correlated with age, DM duration, hemoglobin A1c (HbA1c), and fasting plasma glucose (FPG) while positively correlated with high‐density lipoprotein cholesterol (HDL; P < 0.05). The level of CTRP9 was also significantly associated with the four indexes of CARTs (P < 0.05). Furthermore, CTRP9 was a protective factor for definite CAN (P < 0.05). Compared with the maximum tertile (T3) of the serum CTRP9 levels, a decreased level of serum CTRP9 in T1 significantly increased the prevalence ratio of definite CAN in patients with type 2 diabetes mellitus (P < 0.05). Conclusion: Serum CTRP9 levels were independently associated with definite CAN. CTRP9 represents a reliable biomarker for exploring CAN in patients with type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

Aims/Introduction: This study aimed to evaluate the association between time in range (TIR) obtained from continuous glucose monitoring and the prevalence and degree of painful diabetic neuropathy. Materials and Methods: A total of 364 individuals with diabetic peripheral neuropathy were enrolled in this study. Sensor‐based flash glucose monitoring systems were used to monitor the participants' glucose levels, and the glycemic variability metrics were calculated, including the TIR, glucose coefficient of variation, standard deviation and the mean amplitude of glycemic excursions. The participants were asked to record any form of pain during the 2 weeks of monitoring, and score the pain every day on a numerical rating scale. Based on the numerical rating scale, the patients were divided into the pain‐free group, mild pain group and moderate/severe pain group. Results: Overall, 51.92% (189/364) of the participants were diagnosed with painful diabetic neuropathy. Compared with the pain‐free group, the level of TIR decreased significantly in the mild pain and moderate/severe pain groups (P < 0.05). The prevalence of mild pain and moderate/severe pain decreased with increasing TIR quartiles (all P < 0.05). Multiple linear regression analysis showed that TIR was significantly negatively correlated with the numerical rating scale score after adjustment for glycated hemoglobin, glycemic variability indicators and other risk factors (P < 0.05). Logistic regression analysis showed that a decreasing level of TIR was significantly associated with an increasing risk of any pain and moderate/severe pain (P < 0.05). Conclusions: TIR is correlated with painful diabetic neuropathy and is underscored as a valuable clinical evaluation measure. [ABSTRACT FROM AUTHOR]

Recent works show the promise for lithium tetrafluoroborate (LiBF4) as an electrolyte salt for lithium‐ion batteries. In this paper, LiBF4 is synthesized by a novel reaction between the as‐prepared anhydrous Li2SO3 and (C2H5)2O⋅BF3 in an aprotic solvent. The moisture sensitivity and water‐removing method of LiBF4 materials which has been dried under vacuum for 2 h at different temperature, is studied by Fourier transform infrared spectroscopy measurements. Results show that almost all of the adsorbed water would be removed at above 65 °C. With the increase of drying temperature, crystal water will decrease slowly, and almost disappear completely at 170 °C. However, due to the thermal decomposition of LiBF4, LiF and BF2OH impurities are formed as the temperature reaches 165 °C. So, we determine that the proper drying temperature is 155 °C, though the trace water cannot be removed thoroughly. Besides, influences of trace water on the electrochemical performance of Li/MCMB half‐cell with LiBF4 as electrolyte salt has been investigated. Results show that discharge plateaus at about 1.5 V vs. Li/Li+ will be lengthened with the increase of water content. Subsequently, the so‐called solid‐electrolyte interphase (SEI) film will become thicker and more resistant, which leads to poor Li+ ion migration and bad cycling performance. [ABSTRACT FROM AUTHOR]

Recent works show the promise for lithium tetrafluoroborate (LiBF4) as an electrolyte salt for lithium‐ion batteries. In this paper, LiBF4 is synthesized by a novel reaction between the as‐prepared anhydrous Li2SO3 and (C2H5)2O⋅BF3 in an aprotic solvent. The moisture sensitivity and water‐removing method of LiBF4 materials which has been dried under vacuum for 2 h at different temperature, is studied by Fourier transform infrared spectroscopy measurements. Results show that almost all of the adsorbed water would be removed at above 65 °C. With the increase of drying temperature, crystal water will decrease slowly, and almost disappear completely at 170 °C. However, due to the thermal decomposition of LiBF4, LiF and BF2OH impurities are formed as the temperature reaches 165 °C. So, we determine that the proper drying temperature is 155 °C, though the trace water cannot be removed thoroughly. Besides, influences of trace water on the electrochemical performance of Li/MCMB half‐cell with LiBF4 as electrolyte salt has been investigated. Results show that discharge plateaus at about 1.5 V vs. Li/Li+ will be lengthened with the increase of water content. Subsequently, the so‐called solid‐electrolyte interphase (SEI) film will become thicker and more resistant, which leads to poor Li+ ion migration and bad cycling performance. [ABSTRACT FROM AUTHOR]

The further development of lithium‐ion batteries is often desired to obtain higher capacities by charging to higher potentials. However, such a high potential (>4.3 V) will inevitably result in capacity loss of the LiMn2O4 cathode material over numerous cycles. In this work, degradation mechanisms of LiMn2O4 electrode cycled at different charge cut‐off potentials (4.4, 4.5, 4.6, 4.7, and 4.8 V vs. Li/Li+, respectively) have been investigated. It is found that the capacity degraded seriously after aging cycles at the cut‐off potentials (<4.6 V), especially at 4.4 V. Remarkably, a thicker cathode–electrolyte interface (CEI) film on the cathode surface can be observed when the potential reached 4.7 and 4.8 V. Thus, two degradation mechanisms are proposed, which are also verified by the calculation of the diffusion coefficient of Li+ ions (DLi+). This work demonstrates the relationship between the capacity fade and cut‐off potentials and provides a useful guidance for other cathode materials with high‐voltage operation. Two degradation mechanisms of LiMn2O4 at various cut‐off potentials are proposed: 1) the bulk structure suffers from collapse with cells charged below 4.6 V; 2) higher cut‐off potentials (4.7 and 4.8 V) resulted in a thicker CEI film and enhanced degradation. [ABSTRACT FROM AUTHOR]

The development of a suitable high voltage electrolyte system is of great importance for high energy density system. However, solving the interfacial stability of high voltage cathode materials remains a challenge. Herein, methyl benzenesulfonate (MBS) with a special structure as a "victim" additive has been introduced to construct a protective interface film on the surface of lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) cathode. Charge‐discharge cycling and rate capability performances demonstrate that introducing MBS additive has positive effect on interfacial stability, especially for power property. In 3.0 C rate, the cell with MBS electrolyte has about 63.5 % of capacity retention compared with the discharge capacity using 0.2 C rate, nevertheless, the baseline electrolyte is only 24.2 %. Besides, electrolyte with MBS additive shows some advantages in suppressing overcharge. The excellent performance can be attributed to the special molecular structure of MBS, which can further optimize the properties of interface film. The preferential oxidizability of MBS is able to construct a protective film on the electrode to hinder the further breakdown of electrolyte. The aromatic ring ensures the chemical stability of interface film and the sulfur provides the interface film with high ionic conductivity. These contributions are confirmed by further electrochemical measurements, detailed physical characterizations and theoretical calculations. Victim additive: MBS as a novel additive for high voltage system. Not only the performance of LNMO can be improved, but overcharge protection can be achieved by the addition of MBS. The mechanism of film‐forming for MBS has been proved into by DFT calculation. [ABSTRACT FROM AUTHOR]

The lithium transition-metal phosphate LiFe0.6Mn0.4PO4 has two operating potentials, 3.5 V and 4.1 V, which is favorable for increasing the energy and power densities of lithium-ion batteries (LIBs). To study the compatibility between LiFe0.6Mn0.4PO4 and electrolytes, lithium bis(oxalate)borate (LiBOB) is chosen as the lithium salt, based upon ethylene carbonate (EC), dimethyl carbonate (DMC), and dimethyl sulfite (DMS) as the supporting electrolyte solvents. The electrochemical performances of lithium hexafluorophosphate (LiPF6)-based and LiBOB-based electrolytes are compared. The combination of LiBOB and DMS can facilitate the formation of an effective passivation film. In addition, LiBOB-EC/DMS electrolyte exhibits better cycle and rate performance. The results suggest that LiBOB-EC/DMS electrolyte has good compatibility with LiFe0.6Mn0.4PO4, which makes it an attractive electrolyte for rechargeable LIBs based upon LiFe0.6Mn0.4PO4 cathodes. [ABSTRACT FROM AUTHOR]