Covalent Organic Framework with 3D Ordered Channel and Multi-Functional Groups Endows Zn Anode with Superior Stability

Achieving a highly robust zinc(Zn)metal anode is extremely important for improving the performance of aqueous Zn-ion batteries(AZIBs)for advancing“carbon neutrality”society,which is hampered by the uncontrollable growth of Zn dendrite and severe side reactions including hydrogen evolution reaction,corrosion,and passivation,etc.Herein,an interlayer containing fluorinated zincophilic covalent organic framework with sulfonic acid groups(COF-S-F)is developed on Zn metal(Zn@COF-S-F)as the artificial solid electrolyte interface(SEI).Sulfonic acid group(-SO_(3)H)in COF-S-F can effectively ameliorate the desolvation process of hydrated Zn ions,and the three-dimensional channel with fluoride group(-F)can provide interconnected channels for the favorable transport of Zn ions with ion-confinement effects,endowing Zn@COF-S-F with dendrite-free morphology and suppressed side reactions.Consequently,Zn@COF-S-F symmetric cell can stably cycle for 1,000 h with low average hysteresis voltage(50.5 m V)at the current density of 1.5 m A cm^(-2).Zn@COF-S-F|Mn O_(2)cell delivers the discharge specific capacity of 206.8 m Ah g^(-1)at the current density of 1.2 A g^(-1)after 800 cycles with high-capacity retention(87.9%).Enlightening,building artificial SEI on metallic Zn surface with targeted design has been proved as the effective strategy to foster the practical application of high-performance AZIBs.

Metal-ion-tuned metal-organic frameworks for C_(2)H_(2)/CO_(2) separation

Adsorptive separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))by adsorption is a viable method for producing high-purity C_(2)H_(2) required for industrial applications.However,separating C_(2)H_(2) and CO_(2) is challenging due to their extremely similar molecular sizes and physical properties.Metal-Organic Frameworks(MOFs),as a novel porous material with high specific surface area and tunable pore size,have shown great potential in the separation and purification of light hydrocarbons.Herein,we synthesized three isoreticular Al-MOFs(Al-TCPP,Al-TCPP(Co),and Al-TCPP(Fe))by modulating metal ions at the porphyrin center,all of which can effectively separate C_(2)H_(2)/CO_(2).The addition of metal ions can regulate and improve the separation selectivity of C_(2)H_(2)/CO_(2).Compared with the parent Al-TCPP,the IAST selectivities of Al-TCPP(Co)and Al-TCPP(Fe)for equimolar C_(2)H_(2)/CO_(2) increased from 1.73 to 3.66 and 4.43,respectively.Breakthrough experiments validate their efficient separation of C_(2)H_(2)/CO_(2).Furthermore,they all exhibit excellent hydrothermal stability,laying the foundation for practical applications.

羧基表面修饰与钾离子层间调控双重优化的氮化碳用于增强CO_(2)光还原性能

对石墨相氮化碳(g-C_(3)N_(4))的表面和层间结构进行同时优化,可以显著提高其光生载流子分离效率.然而,将具有特定优势的改性策略有效整合,从而构建由体相到表面的电荷传输通道仍存在巨大挑战.在此,我们提出了一种利用羧基和钾离子共修饰g-C_(3)N_(4)的新方法,用于引导其动态电荷转移过程.具体而言,我们将羧基官能团修饰在表面,通过其吸电子效应产生的驱动力改善表面的载流子动力学.同时,我们将钾离子插入g-C_(3)N_(4)层间,通过连接相邻层间促进载流子的跨层传输.该双功能光催化剂在无需助催化剂或牺牲剂的气固体系中实现了高达17.93μmol g^(-1)h^(-1)的CO产出速率,比未改性的g-C_(3)N_(4)高出8.68倍.这项工作有望进一步加深我们对光催化剂材料体相和层间区域载流子定向迁移机制的理解.

减缓自由阴离子迁移以缓解浓差极化用于高性能的聚合物锂金属电池

Traditional dual-ion lithium salts have been widely used in solid polymer lithium-metal batteries(LMBs).Nevertheless, concentration polarization caused by uncontrolled migration of free anions has severely caused the growth of lithium dendrites. Although single-ion conductor polymers(SICP) have been developed to reduce concentration polarization, the poor ionic conductivity caused by low carrier concentration limits their application. Herein, a dual-salt quasi-solid polymer electrolyte(QSPE), containing the SICP network as a salt and traditional dual-ion lithium salt, is designed for retarding the movement of free anions and simultaneously providing sufficient effective carriers to alleviate concentration polarization. The dual salt network of this designed QSPE is prepared through in-situ crosslinking copolymerization of SICP monomer, regular ionic conductor, crosslinker with the presence of the dual-ion lithium salt,delivering a high lithium-ion transference number(0.75) and satisfactory ionic conductivity(1.16 × 10^(-3) S cm^(-1) at 30 ℃). Comprehensive characterizations combined with theoretical calculation demonstrate that polyanions from SICP exerts a potential repulsive effect on the transport of free anions to reduce concentration polarization inhibiting lithium dendrites. As a consequence, the Li||LiFePO_4 cell achieves a long-cycle stability for 2000 cycles and a 90% capacity retention at 30 ℃. This work provides a new perspective for reducing concentration polarization and simultaneously enabling enough lithiumions migration for high-performance polymer LMBs.

Interfacial ion regulation on 2D layered double hydroxide nanosheets for enhanced thermal insulation

Exploring new strategies to broaden the upper/lower limit of thermal conductivity is of great interest to develop thermal management materials that can adapt to extreme environments.In this work,we employ an interfacial ion regulation to enhance the thermal insulation performance of 2D layered double hydroxide nanosheets.The introduction of interfacial ion enlarges the interplanar spacing of Co(OH)_(2) nanosheets from 4.64 to 8.05 ?,which reduces phonon scattering length perpendicular to the two-dimensional plane and leads to enhanced interlayer thermal insulation.The interfacial ion-regulated Co(OH)_(2)(named as Co(OH)_(2)-M^(x-)) exhibits 3-fold enhancement of thermal insulation through decreasing the thermal conductivity to as low as 0.15 W m^(-1) K^(-1),which is among the top values in 2D solid materials.We anticipate that interfacial ion regulation for 2D nanosheets paves a new avenue to break through the thermal insulation limit.

Boosting 5-ALA-based photodynamic therapy by a liposomal nanomedicine through intracellular iron ion regulation

5-Aminolevulinic acid(5-ALA)has been approved for clinical photodynamic therapy(PDT)due to its negligible photosensitive toxicity.However,the curative effect of 5-ALA is restricted by intracellular biotransformation inactivation of 5-ALA and potential DNA repair of tumor cells.Inspired by the crucial function of iron ions in 5-ALA transformation and DNA repair,a liposomal nanomedicine(MFLs@5-ALA/DFO)with intracellular iron ion regulation property was developed for boosting the PDT of 5-ALA,which was prepared by co-encapsulating 5-ALA and DFO(deferoxamine,a special iron chelator)into the membrane fusion liposomes(MFLs).MFLs@5-ALA/DFO showed an improved pharmaceutical behavior and rapidly fused with tumor cell membrane for 5-ALA and DFO co-delivery.MFLs@5-ALA/DFO could efficiently reduce iron ion,thus blocking the biotransformation of photosensitive protoporphyrin IX(Pp IX)to heme,realizing significant accumulation of photosensitivity.Meanwhile,the activity of DNA repair enzyme was also inhibited with the reduction of iron ion,resulting in the aggravated DNA damage in tumor cells.Our findings showed MFLs@5-ALA/DFO had potential to be applied for enhanced PDT of 5-ALA.