Bifunctional TiO_(2-x)nanofibers enhanced gel polymer electrolyte for high performance lithium metal batteries

Exploration of advanced gel polymer electrolytes(GPEs)represents a viable strategy for mitigating dendritic lithium(Li)growth,which is crucial in ensuring the safe operation of high energy density Li metal batteries(LMBs).Despite this,the application of GPEs is still hindered by inadequate ionic conductivity,low Li^(+)transference number,and subpar physicochemical properties.Herein,Ti O_(2-x)nanofibers(NF)with oxygen vacancy defects were synthesized by a one-step process as inorganic fillers to enhance the thermal/mechanical/ionic-transportation performances of composite GPEs.Various characterizations and theoretical calculations reveal that the oxygen vacancies on the surface of Ti O_(2-x)NF accelerate the dissociation of Li PF_6,promote the rapid transfer of free Li^(+),and influence the formation of Li F-enriched solid electrolyte interphase.Consequently,the composite GPEs demonstrate enhanced ionic conductivity(1.90m S cm^(-1)at room temperature),higher lithium-ion transference number(0.70),wider electrochemical stability window(5.50 V),superior mechanical strength,excellent thermal stability(210℃),and improved compatibility with lithium,resulting in superior cycling stability and rate performance in both Li||Li,Li||Li Fe PO_(4),and Li||Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)cells.Overall,the synergistic influence of nanofiber morphology and enriched oxygen vacancy structure of fillers on electrochemical properties of composite GPEs is comprehensively investigated,thus,it is anticipated to shed new light on designing high-performance GPEs LMBs.

Synergistic Effect of Platinum Single Atoms and Nanoclusters Boosting Electrocatalytic Hydrogen Evolution

Maximizing atomic utilization of precious metalbased catalysts is of great significance in heterogeneous catalysis,also becoming a useful strategy to develop efficient electrocatalysts for hydrogen evolution reaction(HER).Although the dispersion of platinum(Pt)as single atoms(SAs)has increasingly been used in the design of HER electrocatalysts,it is still controversial if the SAs possess higher reactivity relative to the nanoparticles with identical atom loading.

The effect of nano-calcium carbonate onβ-glucosidase immobilized by alginate and chitosan

Nanotechnology has become the most promising domain to boost the efficiency of enzymes.Enzymes are vital as a green catalyst in many industries,food,pharmaceutical and biomedical,etc.The immobilization process of the enzyme increases its catalytic properties.In this research,a novel method is presented to describe the effect of nano-calcium carbonate on the characteristics of immobilizedβ-glucosidase,which was extracted from the Agrocybe aegirit.The nano-CaCO_(3)was produced using the eco-friendly natural deep eutectic solvent.The pure nano-CaCO_(3)was observed as vaterite,with a size of about 300 nm.The nano-calcium carbonate was coated by a natural polymer sodium alginate compound and then adsorbed chitosan.Further,this obtained composite is cross-linked by the bioactive genipin to immobilize theβ-glucosidase.The enzyme/protein loading ratio to the supports was 1:4,respectively.The recovery efficiency of immobilizedβ-glucosidase was 89.3%,and immobilization yield was 96.452%.Chitosan-coated nano-CaCO_(3)was used as a carrier for immobilization ofβ-glucosidase to improve its stability and reusability.In addition to stability and reusability,pH tolerance,temperature tolerance,and enzyme kinetics are the significant parameters that illustrate the proficiency of an immobilized enzyme.The measured optimal enzymatic reaction conditions for the immobilizedβ-glucosidase were 50℃and pH 6.Furthermore,it has shown noticeable improvements in thermo-stability and pH tolerance.Temperature tolerance was observed 50%to the initial activity of the immobilized enzyme even after the 3 h of incubation at 50℃,while pH tolerance was noticed more than 50%and 40%at pH 7 and 8,respectively.The K_(m)and V_(max)values of free and immobilizedβ-glucosidase to 4-nitrophenylβ-D-glucopyranoside were 1.549μmol/L/min,0.346 mmol/L and 0.532μmol/L/min,0.080 mmol/L,respectively.The immobilizedβ-glucosidase retains its storability 80%even after 30 days of storage at 4℃and maintains 93.1%of its residual activity by reusing up to 10 cycles.