The effect of chemical doping on the lithiation processes of the crystalline Si anode ‒ A first-principles study.

We employed first-principles calculations to investigate the effect of chemical doping on the lithiation kinetics and dynamic properties of the c-Si anode. Our ab initio molecular dynamics simulations reveal that phosphorous/arsenic doping can greatly enhance the lithiation kinetics of c-Si, whereas boron doping is unable to produce such an improvement. Our calculations also show that boron doping could enhance Li insertion into c-Si, but phosphorous/arsenic doping tends to increase the insertion energy of Li ions. Although the migration energy barriers of Li ions may slightly increase (decrease) in the boron-(phosphorus-/arsenic-)doped c-Si, these changes were only effective within the range of the nearest-neighbor distance from dopants. Furthermore, it was found that the phosphorus-/arsenic-doped Si can be more ductile and can more easily undergo plastic deformation upon lithiation, while the c-Si matrix becomes more brittle and stiffer when doped with boron. Our simulation results also demonstrate that phosphorous- and arsenic-doping can effectively speed up the Li-induced structural amorphization of c-Si while boron doping appears to severely slow it down. These findings unambiguously indicate that the induced mechanical softening of the c-Si bond network can be the primary factor that leads to the enhanced lithiation kinetics in the n-type doped c-Si anodes.

Metabolites of scutellarein in rat plasma.

The metabolism of scutellarein was investigated in rats. Four metabolites (M1-M4) together with scutellarein were detected and identified as scutellarein-glucuronides in rat plasma by HPLC-DAD, HPLC-MS, and HPLC-MS/MS.

[Study on bile excretion of scutellarein].

OBJECTIVE: A HPLC-ECD method was established to determine scutellarin in rat bile. METHOD: The analytical column was Prontosil C18 (4.6 mm x 250 mm, 5 microm), and the mobile phase was consisted of methanol, 50 mmol x L(-1) phosphate buffer (adjusted by phosphoric acid to pH 2. 6), and tetrahydrofuran (40: 60: 10) , the flow rate was 1.0 mL x min(-1); the potential electrode voltage was 100 mv. RESULT: Concentration profile of scutellarin in rat bile was shown in this paper after oral administration of scutellarein. CONCLUSION: Only scutellarin was detected in rat bile, while both of scutellarin and scutellarein were detected in rat plasma.