Dual-single-atoms of Pt-Co boost sulfur redox kinetics for ultrafast Li-S batteries

Applications of lithium-sulfur(Li-S)batteries are still limited by the sluggish conversion kinetics from polysulfide to Li_(2)S.Although various single-atom catalysts are available for improving the conversion kinetics,the sulfur redox kinetics for Li-S batteries is still not ultrafast.Herein,in this work,a catalyst with dual-single-atom Pt-Co embedded in N-doped carbon nanotubes(Pt&Co@NCNT)was proposed by the atomic layer deposition method to suppress the shuttle effect and synergistically improve the interconversion kinetics from polysulfides to Li_(2)S.The X-ray absorption near edge curves indicated the reversible conversion of Li_(2)Sx on the S/Pt&Co@NCNT electrode.Meanwhile,density functional theory demonstrated that the Pt&Co@NCNT promoted the free energy of the phase transition of sulfur species and reduced the oxidative decomposition energy of Li_(2)S.As a result,the batteries assembled with S/Pt&Co@NCNT electrodes exhibited a high capacity retention of 80%at 100 cycles at a current density of 1.3 mA cm^(−2)(S loading:2.5 mg cm^(−2)).More importantly,an excellent rate performance was achieved with a high capacity of 822.1 mAh g^(−1) at a high current density of 12.7 mA cm^(−2).This work opens a new direction to boost the sulfur redox kinetics for ultrafast Li-S batteries.

Fluoride-Responsive Organogel Based on Hydrazide Derivatives

An organogelator named N-[3-(hydroxy)-4-(dodecyloxy)-benzoyl]-N’ (4’-nitro-benzoyl) hydrazide (D12) was synthesized. It could form stable gels in some of the tested organic solvent. SEM images revealed that the molecules self- assembled into fibrous aggregates in the xerogels. The X-ray diffraction analysis showed that the xerogel exhibited a layered structure. FT-IR studies confirmed that intermolecular hydrogen bonding between C=O and N-H groups was the major driving force for gelation of organic solvents. The gel exhibited gel-sol transition and color change upon addition of F- . An extended conjugated system formed through the phenyl group and a five-membered ring based on intramolecular hydro-gen bonding between the oxygen atom near the deprotonation nitrogen atom and the other NH, which is responsible for the dramatic color change upon addition of F- .

Dynamic crosslinked polymeric nano-prodrugs for highly selective synergistic chemotherapy

To achieve highly selective synergistic chemotherapy attractive for clinical translation,the precise polymeric nano-prodrugs(PPD-NPs)were successfully constructed via the facile crosslinking reaction between p H-sensitive poly(ortho ester)s and reduction-sensitive small molecule synergistic prodrug(Pt(IV)-1).PPD-NPs endowed the defined structure and high drug loading of cisplatin and demethylcantharidin(DMC).Moreover,PPD-NPs exhibited steady long-term storage and circulation via the crosslinked structure,suitable negative potentials and low critical micelle concentration(CMC),improved selective tumour accumulation and cellular internalization via dynamic size transition and surficial amino protonation at tumoural extracellular p H,promoted efficient disintegration and drug release at tumoural intracellular p H/glutathione,and enhanced cytotoxicity via the synergistic effect between cisplatin and DMC with the feed ratio of 1:2,achieving significant tumour suppression while decreasing the side effects.Thus,the dynamic crosslinked polymeric nano-prodrugs exhibit tremendous potential for clinically targeted synergistic cancer therapy.

pH-triggered dynamic erosive small molecule chlorambucil nano-prodrugs mediate robust oral chemotherapy

Currently,the dynamic erosive small molecule nano-prodrug is of great demand for oral chemotherapy,owing to its precise structure,high drug loading and improved oral bioavailability via overcoming various physiologic barriers in gastrointestinal tract,blood circulation and tumor tissues compared to other oral nanomedicines.Herein,this work highlights the successful development of pH-triggered dynamic erosive small molecule nano-prodrugs based on in vivo significant pH changes,which are synthesized via amide reaction between chlorambucil and star-shaped ortho esters.The precise nano-prodrugs exhibit extraordinarily high drug loading(68.16%),electric neutrality,strong hydrophobicity,and dynamic large-to-small size transition from gastrointestinal pH to tumoral pH.These favorable physicochemical properties can effectively facilitate gastrointestinal absorption,blood circulation stability,tumor accumulation,cellular uptake,and cytotoxicity,therefore achieving high oral relative bioavailability(358.72%)and significant tumor growth inhibition while decreasing side effects.Thus,this work may open a new avenue for robust oral chemotherapy attractive for clinical translation.

Long-lifespan thin Li anode achieved by dead Li rejuvenation and Li dendrite suppression for all-solid-state lithium batteries

Solid polymer electrolytes(SPEs)are considered to be one of the most promising systems applied in all-solid-state lithium metal batteries(ASSLMBs)on account of their chemical and electrochemical ro bustness,mechanical stability,cost-effective and scalable manufacturing techniques.Lately,significant en deavors have been directed towards mitigating the formation of the Li dendrite in SPE-based ASSLMBs while research on the inactive lithium in the forms of the solid-electrolyte interface has been rarely re ported.Herein,a bi-functional GaI3additive is developed for in-situ generating Li_(3)Ga alloy for suppressing Li dendrite growth,as well as I3-in recovering dead lithium.Relying on the density functional theory(DFT)results,the Li atom prefers to deposit on the Li_(3)Ga surface and then guide uniform Li deposi tion,while the I3species features a relatively lower lowest unoccupied molecular orbital(LUMO)energy level(-2.12 e V),meaning a higher electron affinity,which is beneficial for reviving inactive lithium to counterbalance the loss of lithium.As a result,in comparison to cells employing pure PEGDME-based electrolytes,the Li-Li symmetric cells utilizing GaI3-containing solid-state electrolyte exhibited a cycling life nearly 30 times longer at a current density/capacity of 0.2 mA/cm^(2),0.2 mAh/cm^(2).The full batterie of LFP//1%GaI3-SPE//40μm Li delivered a noteworthy capacity retention of 82%after 1300 cycles at a rate of 1 C.

Spatiotemporal variation of dissolved oxygen in the Ediacaran surface ocean and its implication for oceanic carbon cycling

The Ediacaran Period(635–539 Ma)witnessed the largest negative excursion in inorganic carbon isotope(δ^(13)Ccarb)over the Earth’s geological history,also known as the Shuram Excursion(SE)event.The occurrence of the SE has been widely attributed to an increase in atmospheric-oceanic oxygen levels and the subsequent oxidation of organic matters in Earth’s surface system.However,the oxygen levels in the Ediacaran ocean during the SE remain poorly constrained,limiting our ability to better understand the cause and mechanisms behind the SE.Recently,the ratio of I/(Ca+Mg)in carbonate has emerged as an effective proxy for quantifying dissolved oxygen([O_(2)])in the local surface seawaters.In this study,we analyzed I/(Ca+Mg)ratios in the Shuiquan Formation at the Mochia-Khutuk(MK)section,which records the SE event in the Tarim continent.The I/(Ca+Mg)ratio shows synchronous variation withδ^(13)Ccarbin the MK section,with the average value decreasing from 2.2μmol/mol at the bottom of the section to 0.8μmol/mol in the middle and then increasing to 3.4μmol/mol at the very top along with the decline and recovery ofδ^(13)Ccarb.According to the relationship between I/(Ca+Mg)and oxygen content in minimum oxygen zones of the modern ocean,we infer that[O_(2)]of surface water in the MK section decreased from>20–70μmol/L to<20–70μmol/L during the SE,which may reflect the upwelling of the deep seawater enriched dissolved organic carbon(DOC)and reduced substance(such as Fe^(2+))together with its subsequent consumption of[O2]in the surface ocean.The I/(Ca+Mg)pattern in the MK section is significantly different from those of other contemporaneous SE records on other continents,indicating the surface[O_(2)]in the Ediacaran ocean could have been temporally and spatially heterogeneous.Local factors,such as latitude,temperature,productivity,and input of anoxic water masses could play important roles in regulating the surface ocean redox conditions.This observation further suggests that the atmospheric oxygen level during the Ediacaran was relatively low and insufficient to dominate the regulation of[O_(2)]in the surface ocean.The results of our study imply that the oxidation of the ocean and in turn the DOC reservoir therein during the SE could be spatially restricted to the continental shelf,rather than the whole ocean.

In-situ polymerized carbonate induced by Li-Ga alloy as novel artificial interphase on Li metal anode

Li metal is considered an ideal anode material because of its high theoretical capacity and low electrode potential.However,the practical usage of Li metal as an anode is severely limited because of inevitable parasitic side reactions with electrolyte and dendrites formation.At present,single-component artificial solid electrolyte interphase cannot simultaneously meet the multiple functions of promoting ion conduction,guiding lithium ion deposition,inhibiting dendrite growth,and reducing interface side reactions.Therefore,multi-component design on Li metal surface is widely investigated to achieve long-term cycling.Herein,we report a Li_(2)Ga-carbonate polymer interphase layer to solve volume changes,Li dendrites formation and side-reactions.As a result,the Li symmetric cell can be stabilized at 3.0 m A/cm^(2)in carbonate electrolyte with limited volume of 20μL.Coupled with 13.6 mg/cm^(2)(loading of 2 mAh/cm^(2))LiFePO_(4)cathode,discharge capacity retains at 90%for over 150 cycles under limited electrolyte conditions.With such an alloy-polymer interphase layer,higher energy density Li metal batteries become prominent in the near future.

More details are needed about the use of multicenter propensity score matching analysis

We read with interest a multicenter propensity score matching(PSM)analysis for patients with a solitary huge hepatocellular carcinoma(HCC),recently published in the HepatoBiliary Surgery and Nutrition(1).Surgical excision remains the primary treatment for solitary HCC,and researchers retrospectively compared the long-term prognosis of patients with balloon-shaped HCCs(BS-HCCs)and non-balloon-shaped HCCs(NBS-HCCs)after liver resection.