A systematic correlation between morphology of porous carbon cathode and electrolyte in lithium-sulfur battery

Porous carbon has been applied for lithium-sulfur battery cathodes,and carbonized metal-organic framework(MOF)is advantageous in tuning the morphology.Herein,we have systematically synthesized water-distorted MOF(WDM)derived porous carbon via controlling the proportion of both water in a mixed solvent(dimethylformamide and water)and ligand in MOF-5 precursors(metal and ligand),which is categorized by its morphology(i.e.Cracked stone(closed),Tassel(open)and Intermediate(semi-open)).For example,decrease in water and increase in ligand content induce Cracked stone WDMs which showed the highest specific surface area(2742-2990 m^(2)/g)and pore volume(2.81-3.28 cm^(3)/g)after carbonization.Morphological effect of carbonized WDMs(CWDMs)on battery performance was examined by introducing electrolytes with different sulfur reduction mechanisms(i.e.DOL/DME and ACN_(2) LiTFSITTE):Closed framework effectively confines polysulfide,whereas open framework enhances electrolyte accessibility.The initial capacities of the batteries were in the following order:Cracked stone>Intermediate>Tassel for DOL/DME and Intermediate>Tassel>Cracked stone for ACN_(2) LiTFSI-TTE.To note,Intermediate CWDM exhibited the highest initial capacity and retained capacity after 100 cycles(1398 and 747 mAh/g)in ACN_(2) LiTFSI-TTE electrolyte having advantages from both open and closed frameworks.In sum,we could correlate cathode morphology(openness and pore structure)and electrolyte type(i.e.polysulfide solubility)with lithium-sulfur battery performance.

Recent development in upconversion nanoparticles and their application in optogenetics:A review

Ion channels present in the plasma membrane are responsible for integration and propagation of electric signals,which transmit information in nerve cells.Malfunction of these ion channels leads to many neurological diseases.Recently,optogenetic technology has gained a lot of attention for the manipulation of neuronal circuits.Optogenetics is a neuromodulation approach that has been developed to control neuronal functions and activities using light.The lanthanide-doped upconversion nanoparticles(UCNPs)absorb low energy photons in near-infrared(NIR) window and emit high energy photons in the visible spectrum region via nonlinear processes.In the last few decades,UCNPs have gained great attention in various bio-medical applications such as bio-imaging,drug delivery and optogenetics.The near-infrared illumination is considered more suitable for optogenetics application,due to its lower degree of light attenuation and higher tissue penetration compared to visible light.Therefore,UCNPs have been considered as the new promising candidates for optogenetics applications.Upconversion nanoparticlemediated optogenetic systems provide a great opportunity to manipulate the ion channel in deep tissue.Herein,we summarize the upconversion photoluminescence in lanthanide doped nanomaterials and its mechanisms and several approaches adopted to tune emission color or enhance upconversion efficiency.Recent advances of lanthanide-doped UCNPs design strategy and their mechanism are reviewed.Then,we discuss the neural circuitry modulation using upconversion nanoparticles mediated optogenetics.Moreover,the future perspectives towards optogenetics are also included.