Progress in polyanion-type cathode materials for lithium ion batteries

Recent progress on the polyanion-type cathode materials for lithium ion batteries is reviewed. Emphasis is placed on the discussion of the relationships between structures and properties of the cathode materials, especially on the role of the polyanion and how to improve their low electronic conductivity

Superior Stability Secured by a Four-Phase Cathode Electrolyte Interface on a Ni-Rich Cathode for Lithium Ion Batteries.

A multifunctional coating with high ionic and electronic conductivity is constructed on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM) to boost the battery stability upon cycling and during storage as well. Phosphoric acid reacts with residual lithium species on the pristine NCM to form a Li3PO4 coating with extra carbon nanotubes (CNTs) penetrating through, which shows high ionic and electronic conductivity. NCM, Li3PO4, CNTs, and the electrolyte jointly form a four-phase cathode electrolyte interface, which plays a key role in the great enhancement of capacity retention, from 50.3% for pristine NCM to 84.8% for the modified one after 500 cycles at 0.5C at room temperature. The modified NCM also delivers superior electrochemical performances at a high cut-off voltage (4.5 V), high temperature (55 °C), and high rate (10C). Furthermore, it can deliver 154.2 mA h g-1 at the 500th cycle after exposed to air with high humidity for 2 weeks. These results demonstrate that the well-constructed multifunctional coating can remarkably enhance the chemical and electrochemical performances of NCM. The improved cycling, storage, and rate performance are attributed to the four-phase cathode electrolyte interface delivering high electron and ionic conductivity and securing the cathode against attack. This work broadens the horizon for constructing effective electrode/electrolyte interfaces for electrochemical energy storage and conversion

Gut microbiota mediates positive effects of liraglutide on dyslipidemia in mice fed a high-fat diet

Except for improving glycemic control, liraglutide, one of the glucagon-like peptide-1 receptor agonists, has exerted promising therapeutic effects for dyslipidemia. It has been proved that gut microbiota plays a dramatic role in regulating lipid metabolism. This study aims to explore whether liraglutide could improve dyslipidemia by modulating the gut microbiota in mice fed a high-fat diet (HFD). The C57BL/6 mice were fed a HFD to establish an animal model of dyslipidemia, and then administered with liraglutide or normal saline (NS) for 12 weeks. Indices of glucolipid metabolism were evaluated. Gut microbiota of the mice was analyzed by 16S rRNA gene sequencing. Compared with HFD group, liraglutide significantly alleviated weight, total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels, meanwhile elevating high-density lipoprotein cholesterol (HDL) levels (all p < 0.05). The gut microbiota analysis revealed that liraglutide greatly reduced the relative abundance of Firmicutes and augmented that of Bacteroidetes, with a concomitant drop in the Firmicutes/Bacteroidetes ratio. Meanwhile, liraglutide dramatically changed the overall composition, promoted the growth of beneficial microbes (Akkermansia, Lactobacillus, Parabacteroides, Oscillospira, etc.), and inhibited the growth of harmful microbes (AF12, Shigella, Proteobacteria, Xenorhabdus, etc.). Especially, the relative abundance of Akkermansia increased the most after liraglutide treatment. Correlation analysis suggested that TC and LDL were positively correlated with some harmful bacteria, and negatively associated with beneficial bacteria. This study confirmed that liraglutide had a certain therapeutic effect on dyslipidemia in HFD-fed mice and could regulate the composition of the gut microbiota associated with lipid metabolism, especially Akkermansia. Thus, affecting gut microbiota might be a potential mechanism of liraglutide in attenuating dyslipidemia