One-Pot Synthesized Amorphous Cobalt Sulfide With Enhanced Electrochemical Performance as Anodes for Lithium-Ion Batteries

In order to solve the poor cycle stability and the pulverization of cobalt sulfides electrodes, a series of amorphous and crystalline cobalt sulfides were prepared by one-pot solvothermal synthesis through controlling the reaction temperatures. Compared to the crystalline cobalt sulfide electrodes, the amorphous cobalt sulfide electrodes exhibited superior electrochemical performance. The high initial discharge and charge capacities of 2,132 mAh/g and 1,443 mAh/g at 200 mA/g were obtained. The reversible capacity was 1,245 mAh/g after 200 cycles, which is much higher than the theoretical capacity. The specific capability was 815 mAh/g at 800 mA/g and increased to 1,047 mAh/g when back to 100 mA/g, indicating the excellent rate capability. The outstanding electrochemical performance of the amorphous cobalt sulfide electrodes could result from the unique characteristics of more defects, isotropic nature, and the absence of grain boundaries for amorphous nanostructures, indicating the potential application of amorphous cobalt sulfide as anodes for lithium-ion batteries.

Reactivating Dead Li by Shuttle Effect for High-Performance Anode-Free Li Metal Batteries

Anode-free Li metal batteries are considered the ultimate configuration for next-generation Li-based batteries due to the nonuse of excess Li metal and high energy density. However, the limited Li source worsens the issues in anode caused by Li dendrites and dead Li. Any Li loss in the formation of SEI and dead Li has a great influence on the full cell. Here, we introduce LiI with shuttle effect to suppress the Li dendrites and reactivate the dead Li in the anode-free LiFePO4 (LFP) |Cu full cells. During cycling, the iodine will transform between I and I3, and a chemical reaction will occur spontaneously between I3 and Li dendrites or dead Li. The generated Li in the electrolyte will be active in the following cycling. The anode-free LFP|Cu cells deliver an initial discharge capacity of 139 mAh g-1 and maintain capacities of 100 mAh g-1 with a capacity retention of 72% after 100 cycles. Both the anode-free LFP|Cu coin cells and pouch cells with LiI additive show much-improved performances. This work provides a new strategy for high-performance anode-free Li metal batteries.

Synthesis, Doping and Electrochemical Properties of Zn3V3O8

The Zn3V3O8 was synthesized by solvothermal method combined with heat treatment using Zn(NO3)3 · 6H2O and NH4VO3 as raw materials. The Zn3V3O8 was doped by Co2+ to form Zn2.88Co0.12V3O8. The samples were characterized by X-ray diffraction and scanning electron microscopy techniques. Electrochemical tests showed that the initial discharge specific capacity for Zn2.88Co0.12V3O8 was 640.4 mAh·g−1 when the current density was 100 mA·g−1, which was higher than that of pure Zn3V3O8 (563.5 mAh · g−1). After 80 cycles, the discharge specific capacity of Zn2.88Co0.12V3O8 could maintain at 652.2 mAh · g−1, which was higher than that of pure Zn3V3O8 (566.8 mAh·g−1) under same condition. The Zn2.88Co0.12V3O8 owned better rate performances than those of pure Zn3V3O8 also. The related modification mechanisms were discussed in this paper

Structure, Morphology and Electrochemical Characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) as Cathode Materials for Na-Ion Batteries

The paper presents the results of the investigations of structural, morphological and electrochemical characteristics of Na x MnO2 (x = 0.44, 0.67 and 0.8) .It is shown that the crystal structure of the resulting materials is determined by the sodium content and is tunnel in a case of Na0.44MnO2 and layered in a case of Na0.67MnO2 and Na0.8MnO2. In addition, the materials obtained are characterized by different morphology. The initial discharge capacity of the materials obtained increases with the increase of sodium content in oxide phase and is 117, 139 and 151 mAh/g for Na0.44MnO2, Na0.67MnO2 and Na0.8MnO2, respectively, however, at the same time the stability of the specific capacity decreases. Using Na0.44MnO2 as an example, the effect of the electrolyte composition, in particular the presence of FEC, on its electrochemical characteristics is shown.

CFD simulation of DC-discharge in airflow

The main purpose of this work is to simulate a dynamics of DC discharge in a subsonic airflow. The calculations were performed in the FlowVision 3.12.01 software package. The single-fluid model (MHD approach) of equilibrium plasma was used while the initial discharge channel was set manually. Cylindrical coaxially arranged electrodes were located in the central part of the calculation area, in the core of the airflow. A 5A DC discharge at atmospheric pressure was considered, as well as a simple model of a re-breakdown between parts of discharge filament. In this work, three-dimensional distributions of temperature and current density were obtained during an evolution of discharge in a flow. Discharge channel extension by the airflow and partial channel decay after the re-breakdown process were shown.

Tris(trimethylsilyl) phosphite (TMSPi) as an electrolyte additive for LiNi0.5Co0.2Mn0.3O2 cathode materials at elevated voltage and temperature

Electrolyte additive tris(trimethylsilyl) phosphite (TMSPi) was used to promote the electrochemical performances of LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2 (NCM523) at elevated voltage (4.5 V) and temperature (55[Formula: see text]C). The NCM523 in 2.0 wt.% TMSPi-added electrolyte exhibited a much higher capacity (166.8 mAh/g) than that in the baseline electrolyte (118.3 mAh/g) after 100 cycles under 4.5 V at 30[Formula: see text]C. Simultaneously, the NCM523 with 2.0 wt.% TMSPi showed superior rate capability compared to that without TMSPi. Besides, after 100 cycles at 55[Formula: see text]C under 4.5 V, the discharge capacity retention reached 87.4% for the cell with 2.0 wt.% TMSPi, however, only 24.4% of initial discharge capacity was left for the cell with the baseline electrolyte. A series of analyses (TEM, XPS and EIS) confirmed that TMSPi-derived solid electrolyte interphase (SEI) stabilized the electrode/electrolyte interface and hindered the increase of interface impedance, resulting in obviously enhanced electrochemical performances of NCM523 cathode materials under elevated voltage and/or temperature.

EP.TH.917An Audit of Compliance with NICE guidelines for Acute Cholecystitis

Background Gallstone disease is common and affects approximately 10-15% of adults. Laparoscopic Cholecystectomy (LC) is the definitive management of cholecystitis. NICE and RCS guidance recommend that in patients diagnosed with acute cholecystitis a LC should be performed during the same admission or within 7 days. We audited our compliance against these national guidelines. Methods Retrospective audit of all patients admitted with uncomplicated acute cholecystitis over a 4 month period. Patient demographics, admission details, timing of cholecystectomy, complications, follow-up, and re-admission data were collected. Results 50 patients (60% female, 40% male; mean age: 60.7 years) with acute cholecystitis were included. Mean length of stay was 4.8 days. Only 10% had a cholecystectomy within 1 week of diagnosis. Of those discharged without a LC on the index admission, 14% were readmitted with further gallstone related complications (cholangitis, pancreatitis) within 48.6 days from initial discharge. The mean time to surgery after initial discharge was 125.8 days. Conclusion There is poor compliance with NICE guidelines to perform an early LC in our cohort of patients, primarily because of the lack of Trust based guidelines. This audit demonstrates the need to develop a robust ‘hot gallbladder’ pathway within our hospital to improve current practice.