The stability of Zn anode in various Znbased energy storage devices is the key problem to be solved.Herein,aromatic aldehyde additives are selected to modulate the interface reactions between the Zn anode and electrol...The stability of Zn anode in various Znbased energy storage devices is the key problem to be solved.Herein,aromatic aldehyde additives are selected to modulate the interface reactions between the Zn anode and electrolyte.Through comprehensively considering electrochemical measurements,DFT calculations and FEA simulations,novel mechanisms of one kind of aromatic aldehyde,veratraldehyde in inhibiting Zn dendrite/by-products can be obtained.This additive prefers to absorb on the Zn surface than H_(2)O molecules and Zn^(2+),while competes with hydrogen evolution reaction and Zn plating/stripping proces s via redox reactions,thus preventing the decomposition of active H_(2)O near the interface and uncontrollable Zn dendrite growth via a synactic absorption-competition mechanism.As a result,Zn-Zn symmetric cells with the veratraldehyde additive realize an excellent cycling life of 3200 h under 1 mA cm^(-2)/1 mAh cm^(-2)and over 800 h even under 5 mA cm^(-2)/5 mAh cm^(-2).Moreover,Zn-Ti and Zn-MnO_(2)cells with the veratraldehyde additive both obtain elevated performance than that with pure ZnSO_(4)electrolyte.Finally,two more aromatic aldehyde additives are chosen to prove their universality in stabilizing Zn anodes.展开更多
Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a ...Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a two-step procedure at room temperature. First, irregularly shaped Ag nanoparticles （INPs） were prepared by reducing silver ammonia solution using ethylal. Second, the agglomerated INPs were selectively etched with HNO3 and C1- to yield {100} facet-rich mesoporous Ag nanocubes. The mechanism of Ag-nanocube formation and growth was investigated in detail by elucidating the involved chemical reactions and physical changes at each step during the synthesis. The addition of C1- anions was responsible for facilitating Ag nanoparticle growth by removing surface-adsorbed Ag＋ species, thereby eliminating inter-particle repulsive forces. This agglomeration was found crucial for the subsequent selective oxidation of Ag nanoparticles because the protective agent used, polyvinylpyrrolidone （PVP）, was the most effective one for adsorption on the surfaces of Ag nanoparticles of size greater than approximately 50 nm. Importantly mesopores were found inside the Ag nanocubes; this can be attributed to the unavoidable imperfect packing during the agglomeration of INPs. The newly prepared Ag nanocubes were further used to enhance the Raman signal of rhodamine 6G, which is capable of reducing the detection limitation to 10-16 mol·L-1.展开更多
基金support by National Natural Science Foundation of China(51271205,50801070)‘‘Project of Science and Technology Plan’’by Qingyuan city(DZXQY052,2018C005,2019A026)+2 种基金Project of results transformation achievement fund by Sun Yat-sen University(31000-18843232)‘‘Tian’e Plan’’by Huizhou city(20170220011822281,20170220085037390)the Scientifc Technology Project of Guangzhou City(202103000003).
文摘The stability of Zn anode in various Znbased energy storage devices is the key problem to be solved.Herein,aromatic aldehyde additives are selected to modulate the interface reactions between the Zn anode and electrolyte.Through comprehensively considering electrochemical measurements,DFT calculations and FEA simulations,novel mechanisms of one kind of aromatic aldehyde,veratraldehyde in inhibiting Zn dendrite/by-products can be obtained.This additive prefers to absorb on the Zn surface than H_(2)O molecules and Zn^(2+),while competes with hydrogen evolution reaction and Zn plating/stripping proces s via redox reactions,thus preventing the decomposition of active H_(2)O near the interface and uncontrollable Zn dendrite growth via a synactic absorption-competition mechanism.As a result,Zn-Zn symmetric cells with the veratraldehyde additive realize an excellent cycling life of 3200 h under 1 mA cm^(-2)/1 mAh cm^(-2)and over 800 h even under 5 mA cm^(-2)/5 mAh cm^(-2).Moreover,Zn-Ti and Zn-MnO_(2)cells with the veratraldehyde additive both obtain elevated performance than that with pure ZnSO_(4)electrolyte.Finally,two more aromatic aldehyde additives are chosen to prove their universality in stabilizing Zn anodes.
文摘Silver nanocubes enriched with {100} facets have been extensively used for surface-enhanced Raman scattering. Herein, we report a new water-phase synthesis method for weU-defined Ag nanocubes with tunable sizes via a two-step procedure at room temperature. First, irregularly shaped Ag nanoparticles （INPs） were prepared by reducing silver ammonia solution using ethylal. Second, the agglomerated INPs were selectively etched with HNO3 and C1- to yield {100} facet-rich mesoporous Ag nanocubes. The mechanism of Ag-nanocube formation and growth was investigated in detail by elucidating the involved chemical reactions and physical changes at each step during the synthesis. The addition of C1- anions was responsible for facilitating Ag nanoparticle growth by removing surface-adsorbed Ag＋ species, thereby eliminating inter-particle repulsive forces. This agglomeration was found crucial for the subsequent selective oxidation of Ag nanoparticles because the protective agent used, polyvinylpyrrolidone （PVP）, was the most effective one for adsorption on the surfaces of Ag nanoparticles of size greater than approximately 50 nm. Importantly mesopores were found inside the Ag nanocubes; this can be attributed to the unavoidable imperfect packing during the agglomeration of INPs. The newly prepared Ag nanocubes were further used to enhance the Raman signal of rhodamine 6G, which is capable of reducing the detection limitation to 10-16 mol·L-1.
