Boron-doped high-entropy oxide toward high-rate and long-cycle layered cathodes for wide-temperature sodium-ion batteries

03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na^(+)diffusion kinetics pose significant challenges to achieve high-performance layered cathodes.Herein,a boron-doped03-type high entropy oxide Na(Fe_(0.2)Co_(0.15)Cu_(0.05)Ni_(0.2)Mn_(0.2)Ti_(0.2))B_(0.02)O_(2)(NFCCNMT-B_(0.02))is designed and the covalent B-O bonds with high entropy configuration ensure a robust layered structure.The obtained cathode NFCCNMT-B_(0.02)exhibits impressive cycling performance(capacity retention of 95%and 82%after100 cycles and 300 cycles at 1 and 10 C,respectively)and outstanding rate capability(capacity of 83 mAh g^(-1)at 10 C).Furthermore,the NFCCNMT-B_(0.02)demonstrates a superior wide-temperature performance,maintaining the same capacity level(113,4 mAh g^(-1)@-20℃,121 mAh g^(-1)@25℃,and 119 mAh g^(-1)@60℃)and superior cycle stability(90%capacity retention after 100 cycles at 1 C at-20℃).The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance.The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes(ΔV=0.65 A3).B ions doping expands the Na layer distance and enlarges the P3 phase region,thereby enhancing Na^(+)diffusion kinetics.This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.

Hard carbons derived from pine nut shells as anode materials for Na-ion batteries

Hard carbons as promising anode materials for Na-ion batteries(NIBs) have captured extensive attention because of their low operation voltage, easy synthesis process, and competitive specific capacity. However, there are still several disadvantages, such as high cost and low initial coulombic efficiency, which limit their large-scale commercial applications.Herein, pine nut shells(PNSs), a low-cost biomass waste, are used as precursors to prepare hard carbon materials. Via a series of washing and heat treatment procedures, a pine nut shell hard carbon(PNSHC)-1400 sample has been obtained and delivers a reversible capacity of around 300 mAh/g, a high initial coulombic efficiency of 84%, and good cycling performance. These excellent Na storage properties indicate that PNSHC is one of the most promising candidates of hard carbon anodes for NIBs.

Formation of the structure-Ⅱgas hydrate from low-concentration propane mixed with methane

It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas hydrate.However,its mechanism is still not well understood yet.In this research,structure-Ⅱ(sⅡ)hydrate is synthesized using a methanepropane gas mixture with an initial mole ratio of 99:1,and it is found that large(5~(12)6~4)cages are cooccupied by multiple gases based on the rigid structure analysis of neutron diffraction data.The first principles calculation and molecular dynamics simulation are conducted to uncover the molecular mechanism for sⅡmethane-propane hydrate formation,revealing that the presence of propane inhibits the formation of structure-Ⅰ(sⅠ)hydrate but promotes sⅡhydrate formation.The results help to understand the accumulation mechanism of natural gas hydrate and benefit to optimize the condition for gas storage and transportation in hydrate form.

Designing a P2-type cathode material with Li in both Na and transition metal layers for Na-ion batteries

P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.

Tuning anionic/cationic redox chemistry in a P2-type Na0.67Mn0.5Fe0.5O2 cathode material via a synergic strategy

The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much attention.However,determining how to tune the anionic redox reaction is still a major challenge.Herein,we tune the activity and reversibility of both the anionic and cationic redox reactions of Na0.67Mn0.5Fe0.5O2 though an integrated strategy that combines the advantages of Li2SiO3 coating,Li doping and Si doping,and the initial capacity,rate performance and cycling stability are significantly improved.The in-depth modulation mechanism is revealed by means of neutron diffraction,X-ray absorption spectroscopy,in situ X-ray diffraction,electron paramagnetic resonance spectroscopy,first-principles calculations and so on.The Li2SiO3 coating alleviates the side reactions and enhances the cycling stability.Si^4+doping lowers the Na^+diffusion barrier due to the expanded interlayer spacing.Additionally,Si^4+doping improves the structural stability,oxygen redox activity and reversibility.Li^+doping in Na sites further increases the structure stability.The electron density maps confirm the greater activity of Na and O in the modified sample.Nuclear density maps and bond-valence energy landscapes identify the Na^+migration pathway from Nae site to Naf site(the positions of the Na ions in the crystal structure).The proposed insights into the modulation mechanism of the anionic and cationic redox chemistry are also instructive for designing other oxide-based cathode materials.

Comparison of survival prediction values of different scoring models for patients undergoing transjugular intrahepatic portal shunt:A multicenter retrospective study

Aim:The aim of this study is to compare the prognostic values of the Child–Pugh,integrated model for end‐stage liver disease(iMELD),albumin–bilirubin(ALBI),and Freiburg index of postsurvival(FIPS)scores in patients undergoing transjugular intrahepatic portosystemic shunt(TIPS).Methods:We conducted a multicenter retrospective study including patients who underwent TIPS by collecting data from several hospitals in southwest China between January 2014 and February 2021.We compared the performance of different scoring models for survival prediction in these patients.The performance of each scoring model was assessed via area under the receiver‐operating characteristic(AUROC)curve analysis.Results:The study included 378 TIPS patients(268 men,110 women;median age 52[interquartile range,45–60]years).Age;cirrhosis etiology;ascites severity;albumin levels;international normalized ratio;total bilirubin levels;sodium levels;and Child–Pugh,iMELD,ALBI,and FIPS scores were significant prognostic factors in cirrhotic patients who underwent TIPS.The Child–Pugh,iMELD,ALBI,and FIPS scores were all independent predictors of survival in TIPS patients.Survival analysis showed that all scoring models effectively stratified the prognostic risk of these patients.The Child–Pugh score was the best predictor of postoperative survival,followed by the ALBI and FIPS scores.The iMELD score was the worst predictor.The Child–Pugh,iMELD,ALBI,and FIPS scores predicted the 1‐year postoperative survival,with AUROC values of 0.832,0.677,0.761,and 0.745,respectively,and the 3‐year postoperative survival,with AUROC values of 0.710,0.668,0.721,and 0.658,respectively.The calibration curve showed that the Child–Pugh,ALBI,and FIPS models performed well in predicting 1‐and 3‐year survival,whereas the iMELD model was a poor predictor.Conclusions:The four scoring models can predict survival in cirrhotic patients after TIPS and can effectively stratify prognostic risk.The Child–Pugh score may be more suitable for predicting survival after TIPS in patients with liver cirrhosis.

Phytic acid-modified CeO_(2) as Ca^(2+) inhibitor for a security reversal of tumor drug resistance

Ca^(2+)plays critical roles in the development of diseases,whereas existing various Ca regulation methods have been greatly restricted in their clinical applications due to their high toxicity and inefficiency.To solve this issue,with the help of Ca overexpressed tumor drug resistance model,the phytic acid(PA)-modified CeO_(2) nano-inhibitors have been rationally designed as an unprecedentedly safe and efficient Ca2+inhibitor to successfully reverse tumor drug resistance through Ca^(2+)negative regulation strategy.Using doxorubicin(Dox)as a model chemotherapeutic drug,the Ca^(2+)nano-inhibitors efficiently deprived intracellular excessive free Ca2+,suppressed P-glycoprotein(P-gp)expression and significantly enhanced intracellular drug accumulation in Dox-resistant tumor cells.This Ca^(2+)negative regulation strategy improved the intratumoral Dox concentration by a factor of 12.4 and nearly eradicated tumors without obvious adverse effects.Besides,nanocerias as pH-regulated nanozyme greatly alleviated the adverse effects of chemotherapeutic drug on normal cells/organs and substantially improved survivals of mice.We anticipate that this safe and effective Ca^(2+)negative regulation strategy has potentials to conquer the pitfalls of traditional Ca inhibitors,improve therapeutic efficacy of common chemotherapeutic drugs and serves as a facile and effective treatment platform of other Ca^(2+) associated diseases.