In situ Raman spectroscopy reveals the mechanism of titanium substitution in P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2): Cathode materials for sodium batteries

Layered P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 is a promising cathode material. It exhibits a high capacity and suitable operating voltage and undergoes a phase transition from P2 to O2 during charge/discharge.Researchers have used Ti substitution to improve the cathode, yet the chemical principles that underpin elemental substitution and functional improvement remain unclear. To clarify these principles, we used in situ Raman spectroscopy to monitor chemical changes in P2–Na2/3 Ni1/3 Mn1/3 Ti1/3 O2 and P2–Na_(2/3)Ni_(1/3)Mn_(2/3)O_2 during charge/discharge. Based on the change in the A_(1g) and E_g peaks during charge/discharge, we concluded that Ti substitution compressed the transition metal layer and expanded the planar oxygen layer in the unit cell. Titanium stabilized the P2 phase structure, which improved the cycling stability of P2–NaNMT. Our results provide clear theoretical support for future research on modifying electrodes by elemental substitution.

Regeneration of photovoltaic industry silicon waste toward high-performance lithium-ion battery anode

The diamond-wire sawing silicon waste(DWSSW)from the photovoltaic industry has been widely considered as a low-cost raw material for lithium-ion battery silicon-based electrode,but the effect mechanism of impurities presents in DWSSW on lithium storage performance is still not well understood;meanwhile,it is urgent to develop a strategy for changing DWSSW particles into high-performance electrode materials.In this work,the occurrence state of impurities presents in DWSSW was carefully analyzed using in situ Ar ion etching technology Then,the novel Si@C@SiO_(x)@PAl-NDC composite was designed through in situ encapsulation strategy.The obtained Si@C@SiO_(x)@PAl-NDC electrode shows a high first capacity of 2343.4 mAh·g^(-1)with an initial Coulombic efficiency(ICE)of 84.4%under current density of 1.0 A·g^(-1),and can deliver an impressive capacity of 984.9 mAh·g^(-1)after 200 cycles.Combined numerical simulation modeling calculations,the increase in proportion of Si^(4+)/Si^(0)and Si^(3+)/Si^(0)valence states in SiO_(x)layer leads to a decrease in von Mises stress,which ultimately improves the cycling structural stability.Meanwhile,the porous 2D-3D aluminum/nitrogen(Al/N)co-doped carbon layer and nanowires on SiO_(x)layer can provide abundant active sites for lithium storage due to its developed hierarchical pores structure,which facilitates ion transport What is more,the performance of Si@C@SiO_(x)@PAl-NDC//LiFePO_(4)full cell shows its great potential in practical application.

A widely used nonionic surfactant with desired functional groups as aqueous electrolyte additives for stabilizing Zn anode

Aqueous Zn-ion batteries(AZIBs) have emerged as potential candidates for Li-ion batteries due to their intrinsic safety and high capacity.However,metallic Zn anodes encounter dendrite growth and water-induced corrosion,rendering poor stability and severe irreversibility at the electrode/electrolyte interface during cycling.To stabilize the Zn anode,we report a low-cost and effective nonionic surfactant,Tween-20 polymer,as an electrolyte additive for AZIBs.For Tween-20,sequential oxyethylene groups tended to be preferentially adsorbed on the Zn electrode to form a shielding layer for regulating uniform Zn nucleation.Moreover,the hydrophobic hendecyl chains prevented H_(2)O-induced corrosion on the Zn anode surface.Benefiting from the desired functional groups,when only trace amounts of Tween-20(0.050 g·L^(-1)) were used,the Zn anode displayed good cycling stability over 2170 h at10 mA·cm^(-2) and a high average Coulombic efficiency of98.94% over 1000 cycles.The Tween-20 polymer can also be effectively employed in MnO_(2)/Zn full batteries.Considering their toxicity,price and amount of usage,these surfactant additives provide a promising strategy for realizing the stability and reversibility of high-performance Zn anodes.

Scalable synthesis of mesoporous FeS_(2) nanorods as highperformance anode materials for sodium-ion batteries

Sodium-ion batteries(SIBs),as highly promising alternatives to lithium-ion batteries(LIBs),can be widely used in a variety of next-generation energy storage systems.However,the current commercial graphite anodes of LIBs could not intercalate sodium ions to appreciable extent,and the electrochemical irreversibility hinders further application.Searching for a suitable anode material is a critical issue for the successful development of SIBs.Herein,we report a convenient,fast,and large-scale preparation method of mesoporous FeS_(2) nanorods.Our specially designed one-dimensional mesoporous structure of FeS_(2) takes full advantage of ultra-high strain relaxation as well as fast Na^(+)transport rate arising from microstructural characteristics.As a result,the mesoporous FeS_(2) nanorods exhibited excellent sodium storage performance.The discharge capacity was retained at 711.1 mAh·g^(-1) after 450 cycles at a current density of 1000 mA·g^(-1).The special microstructure and superior performance of mesoporous FeS_(2) nanorods represent a critical step for transition metal sulfides electrode materials toward practical SIBs application.

Determination and Pharmacokinetic Study of Nitidine Chloride in Rat Plasma after Intragastrical Administration by LC-ESI-MS/MS Method

Objective To study the pharmacokinetics of nitidine chloride（NC） in rat plasma after intragastrical（i.g.） administration. Methods A liquid chromatography-electrospray ionization-mass/mass sprectrometry（LC-ESI-MS/MS） was used and carbamazepine was used as an intermal standard（I.S.）. The rat plasma samples were deproteinized with acetonitrile and the resultant supernatant was assayed on an analytical Diamonsil ^（TM）ODS C_（18） column（2.1 mm × 150 mm） equipped with a C_（18） guard column（4 mm × 20 mm） with a mobile phase of acetonitrile–10 mM ammonium acetate buffer–formic acid（35： 65： 0.2, v/v/v） at the flow rate of 0.25 mL/min. The LC–MS was carried out on a triple-quadrupole mass spectrometry equipped with an ESI and positive selected-ion monitoring. Target ions were monitored at [M-Cl]~＋ m/z 348.2 for NC and [M ＋ H]~＋ m/z237.2 for I.S., respectively. Results The simple one step deproteinize and rapid analysis method were successfully used in pharmacokinetic study on NC after i.g. administration. The linear relationship was good over the range of 2.5 – 1000.0 ng/ml（r^2 = 0.999 2） in rat plasma. The lower limit of quantification and detection were 2.5 and 1.6 ng/ml, respectively. The extraction recovery was in the range of 86.54 – 98.60%. The intra-and inter-day precisions（relative standard deviation） were less than 6.00%, with accuracies deviation between 89.40 to 95.57%. A two-compartment pharmacokinetic open model was proposed and validated to explain the apparent biphasic disposition of NC in rat plasma after i.g. administration. Conclusion This study was successfully applied to a pharmacokinetic study of NC in rats plasma following i.g. administration and could be used for preclinical and clinical pharmacokinetic evaluation of NC.