Facile fabrication of regenerated cellulose-based separators for high-performance lithium-ion batteries by regulating degrees of polymerization.

Cellulose-based separators have great application prospects in the field of lithium-ion batteries (LIBs) due to their excellent wettability and thermal stability. However, most current cellulose-based separators come from high-cost nanocellulose and bacterial cellulose. Herein, regenerated cellulose (RC) separators were prepared from dissolving pulp with different degrees of polymerization (DPs) by using the NaOH/urea/thiourea dissolution system as well as a nonsolvent-induced phase separation method. The results showed that the DP of cellulose had a significant influence on the mechanical properties, pore structure, and electrochemical properties of the resultant RC separator. An appropriate increase in the DP could improve the mechanical strength, porosity, and ionic conductivity of the separator. The RC separator with a DP of 599 exhibited the best performance with a porosity of 56.1 %, an average pore size of 305 nm, an electrolyte uptake of 339 %, a tensile strength of 38.3 MPa, and an ionic conductivity of 1.88 mS·cm-1. The lithium-ion battery prepared with the optimal RC separator had a specific capacity of 156.55 mAh/g for 100 cycles at a current density of 0.5 C and a coulombic efficiency of more than 96 %, which was a clear advantage over the commercially available Celgard2400 and cellulose separators. This work makes contributions to the development of high-performance LIBs separators from cellulose.

Medium and long-term complications difference between laparoscopic transcystic common bile duct exploration versus endoscopic sphincterotomy against choledocholithiasis: A protocol for systematic review and meta-analysis.

BACKGROUND: Common bile duct stone (CBDS) is typically manifested with abdominal pain, chills, fever, and jaundice. Laparoscopic transcystic common bile duct exploration (LTCBDE) and endoscopic sphincterotomy (EST) are currently the main minimally invasive methods for the treatment of CBDS. However, there are few studies about the differences of medium and long-term complication after EST or LTCBDE. Therefore, we will conduct a meta-analysis and systematic review to systematically evaluate the difference of medium and long-term complications between EST and LTCBDE against CBDS. METHODS: Randomized controlled trials of EST or LTCBDE against CBDS will be searched in several English and Chinese databases with the following vocabularies: "laparoscopic transcystic common bile duct exploration," "endoscopic sphincterotomy," "choledocholithiasis," "common bile duct stone" until December, 2020. Two reviewers will independently conduct the literature extraction, risk of bias assessment, and statistical analysis. RESULTS AND CONCLUSIONS: The study will help to systematically evaluate the difference of medium and long-term complication between EST and LTCBDE against CBDS. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/5U7SA.