Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical proper...Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical properties,leading to uncontrolled zinc(Zn)dendrite formation and undesirable side reactions.To address these limitations and enhance the electrochemical performance of AZIBs,a precisely designed functional separator is developed by incorporating UiO-66-(COOH)_(2)into a poly(vinylidene fluoride)(PVDF)framework(U-PVDF)via a direct in situ growth method.This approach enables uniform distribution of UiO-66-(COOH)_(2)both on the surface and within the PVDF backbone,without increasing separator thickness.Owing to the strong interaction between Zn^(2+)and the abundant carboxyl groups in UiO-66-(COOH)_(2),the U-PVDF separator regulates the Zn^(2+)solvation structure toward a contact ion pair-dominated structure by reducing coordinated water molecules,which effectively mitigates water-induced parasitic reactions and promotes compact Zn deposition.Consequently,a Zn/Zn symmetric cell employing the U-PVDF separator demonstrates superior cycling stability over 1500 cycles without internal short-circuiting at a current density of 6 mA cm^(−2)and an areal capacity of 2 mAh cm^(−2).Moreover,Zn/NaV_(3)O_(8)·xH_(2)O(NVO)cell with the U-PVDF separator exhibits markedly improved cyclability and rate performance compared with those using conventional GF separator.展开更多
Aqueous Zn-ion storage offers high capacity and safety,but practical use is hindered by dendrite formation,side reactions,and hydrogen evolution,affecting stability and efficiency.Herein,tetramethylol acetylenediurea(...Aqueous Zn-ion storage offers high capacity and safety,but practical use is hindered by dendrite formation,side reactions,and hydrogen evolution,affecting stability and efficiency.Herein,tetramethylol acetylenediurea(TA)is proposed as an effective electrolyte additive that modulates the Zn^(2+)deposition environment via coordination competition.The polar functional groups of TA restructure the solvation sheath,while its molecular dipoles generate localized electric fields that accelerate Zn^(2+)migration and promote directional(002)-oriented deposition.These effects collectively suppress side reactions and enhance Zn plating/stripping reversibility.The four hydroxyl(–OH)and conjugated ketone groups(C=O)in the TA molecule have strong coordination ability(Lewis basicity)and can form a stable[Zn(TA)(H_(2)O)_(n)]^(2+)with Zn^(2+),reducing the number of free water molecules and the proportion of active water in the solvation sheath.The TA molecules are adsorbed onto the Zn anode surface,leading to the redistribution of the local spatial electric field and homogenization of ion flux dynamics.Its conjugated planar structure can induce Zn^(2+)to preferentially deposit along the(002)crystal plane.Zn//Zn symmetric cell using TA-containing ZnSO4 electrolyte exhibits stable cycling for more than 2240 h at 1 mA cm^(−2),1 mAh cm^(−2).The Zn//activated carbon(AC)full-cell can stably cycle 30,000 cycles at 5 A g^(−1)with a capacity retention rate of 90%.This study provides important insights into electrolyte engineering strategies for stabilizing Zn anodes,highlighting the potential of molecular design additives in next-generation Zn^(2+)energy storage systems.展开更多
基金supported by the Basic Science Research Program(RS-2024-00455177)through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT.
文摘Aqueous zinc ion batteries(AZIBs)are considered promising candidates owing to their inherent safety and low cost.However,the conventional glass fiber(GF)separator used in AZIBs suffers from poor physicochemical properties,leading to uncontrolled zinc(Zn)dendrite formation and undesirable side reactions.To address these limitations and enhance the electrochemical performance of AZIBs,a precisely designed functional separator is developed by incorporating UiO-66-(COOH)_(2)into a poly(vinylidene fluoride)(PVDF)framework(U-PVDF)via a direct in situ growth method.This approach enables uniform distribution of UiO-66-(COOH)_(2)both on the surface and within the PVDF backbone,without increasing separator thickness.Owing to the strong interaction between Zn^(2+)and the abundant carboxyl groups in UiO-66-(COOH)_(2),the U-PVDF separator regulates the Zn^(2+)solvation structure toward a contact ion pair-dominated structure by reducing coordinated water molecules,which effectively mitigates water-induced parasitic reactions and promotes compact Zn deposition.Consequently,a Zn/Zn symmetric cell employing the U-PVDF separator demonstrates superior cycling stability over 1500 cycles without internal short-circuiting at a current density of 6 mA cm^(−2)and an areal capacity of 2 mAh cm^(−2).Moreover,Zn/NaV_(3)O_(8)·xH_(2)O(NVO)cell with the U-PVDF separator exhibits markedly improved cyclability and rate performance compared with those using conventional GF separator.
基金supported by the National Natural Science Foundation of China(22269020,42167068,U23A20582)the Gansu Province Higher Education Industry Support Plan Project(2023CYZC-17,2023CYZC-68)+1 种基金the Key Project of Natural Science Foundation of Gansu Province(25JRRA004)2024 Major Cultivation Project for University Research and Innovation Platforms(2024CXPT-10).
文摘Aqueous Zn-ion storage offers high capacity and safety,but practical use is hindered by dendrite formation,side reactions,and hydrogen evolution,affecting stability and efficiency.Herein,tetramethylol acetylenediurea(TA)is proposed as an effective electrolyte additive that modulates the Zn^(2+)deposition environment via coordination competition.The polar functional groups of TA restructure the solvation sheath,while its molecular dipoles generate localized electric fields that accelerate Zn^(2+)migration and promote directional(002)-oriented deposition.These effects collectively suppress side reactions and enhance Zn plating/stripping reversibility.The four hydroxyl(–OH)and conjugated ketone groups(C=O)in the TA molecule have strong coordination ability(Lewis basicity)and can form a stable[Zn(TA)(H_(2)O)_(n)]^(2+)with Zn^(2+),reducing the number of free water molecules and the proportion of active water in the solvation sheath.The TA molecules are adsorbed onto the Zn anode surface,leading to the redistribution of the local spatial electric field and homogenization of ion flux dynamics.Its conjugated planar structure can induce Zn^(2+)to preferentially deposit along the(002)crystal plane.Zn//Zn symmetric cell using TA-containing ZnSO4 electrolyte exhibits stable cycling for more than 2240 h at 1 mA cm^(−2),1 mAh cm^(−2).The Zn//activated carbon(AC)full-cell can stably cycle 30,000 cycles at 5 A g^(−1)with a capacity retention rate of 90%.This study provides important insights into electrolyte engineering strategies for stabilizing Zn anodes,highlighting the potential of molecular design additives in next-generation Zn^(2+)energy storage systems.
