Solubilities of ammonium tetraphenylborate (NH4BPh4) in water- t- butyl alcohol (TBA) mixed solvents at 283.15,293.15,298.15,303.15 and 308.15 K have been determined by spectrophotometry.The standard Gibbs energy of t...Solubilities of ammonium tetraphenylborate (NH4BPh4) in water- t- butyl alcohol (TBA) mixed solvents at 283.15,293.15,298.15,303.15 and 308.15 K have been determined by spectrophotometry.The standard Gibbs energy of transfer (Δ G t) of NH4BPh4 from water to H2O- TBA mixtures and the primary medium effect of NH4BPh4 from 283.15 to 308.15 K were studied.The results show that－Δ G t exhibits a complicated variation pattern with the increase in the mole fraction of TBA [x(TBA)] at the same temperature .When x(TBA) < 0.06,－Δ G t increases very slowly with x(TBA),the－Δ G t increases rapidly with x(TBA) when x(TBA) from 0.06 to 0.2.For x(TBA)> 0.2,the－Δ G t decreases with increasing x(TBA).The largest value of －Δ G t occurs at x(TBA) = 0.2.The main reason for this variation was analyzed and discussed.展开更多
The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an addi...The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an additive to reshape the solvation structure and modulate the interface chemistry.The strong interactions among sorbitol and both water molecules and Zn electrode can reduce the free water activity,optimize the solvation shell of water and Zn^(2+)ions,and regulate the formation of local water(H_(2)O)-poor environment on the surface of Zn electrode,which effectively inhibit the decomposition of water molecules,and thus,achieve the thermodynamically stable and highly reversible Zn electrochemistry.As a result,the assembled Zn/Zn symmetric cells with the sorbitol additive realized an excellent cycling life of 2000 h at 1 mA·cm^(-2)and 1 mAh·cm^(-2),and over 250 h at 5 mA.cm^(-2)and 5 mAh.cm^(-2).Moreover,the Zn/Cu asymmetric cells with the sorbitol additive achieved a high Coulombic efficiency of 99.6%,obtaining a better performance than that with a pure 2 mol-L^(-1)ZnSO_(4)electrolyte.And the constructed Zn/poly1,5-naphthalenediamine(PNDA)batteries could be stably discharged for 2300 cycles at 1 A g^(-1)with an excellent capacity retention rate.This result indicates that the addition of 1 mol-L^(-1)non-toxic sorbitol into a conventional ZnSO_(4)electrolyte can successfully protect the Zn anode interface by improving the electrochemical properties of Zn reversible deposition/decomposition,which greatly promotes its cycle performance,providing a new approach in future development of high performance aqueous Zn ion batteries.展开更多
文摘Solubilities of ammonium tetraphenylborate (NH4BPh4) in water- t- butyl alcohol (TBA) mixed solvents at 283.15,293.15,298.15,303.15 and 308.15 K have been determined by spectrophotometry.The standard Gibbs energy of transfer (Δ G t) of NH4BPh4 from water to H2O- TBA mixtures and the primary medium effect of NH4BPh4 from 283.15 to 308.15 K were studied.The results show that－Δ G t exhibits a complicated variation pattern with the increase in the mole fraction of TBA [x(TBA)] at the same temperature .When x(TBA) < 0.06,－Δ G t increases very slowly with x(TBA),the－Δ G t increases rapidly with x(TBA) when x(TBA) from 0.06 to 0.2.For x(TBA)> 0.2,the－Δ G t decreases with increasing x(TBA).The largest value of －Δ G t occurs at x(TBA) = 0.2.The main reason for this variation was analyzed and discussed.
基金supported by the National Natural Science Foundation of China(22279063,52001170)Tianjin Natural Science Foundation(22JCYBJC00590)the Fundamental Research Funds for the Central Universities.We thank the Haihe Laboratoryof Sustainable Chemical Transformations for financial support.
文摘The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an additive to reshape the solvation structure and modulate the interface chemistry.The strong interactions among sorbitol and both water molecules and Zn electrode can reduce the free water activity,optimize the solvation shell of water and Zn^(2+)ions,and regulate the formation of local water(H_(2)O)-poor environment on the surface of Zn electrode,which effectively inhibit the decomposition of water molecules,and thus,achieve the thermodynamically stable and highly reversible Zn electrochemistry.As a result,the assembled Zn/Zn symmetric cells with the sorbitol additive realized an excellent cycling life of 2000 h at 1 mA·cm^(-2)and 1 mAh·cm^(-2),and over 250 h at 5 mA.cm^(-2)and 5 mAh.cm^(-2).Moreover,the Zn/Cu asymmetric cells with the sorbitol additive achieved a high Coulombic efficiency of 99.6%,obtaining a better performance than that with a pure 2 mol-L^(-1)ZnSO_(4)electrolyte.And the constructed Zn/poly1,5-naphthalenediamine(PNDA)batteries could be stably discharged for 2300 cycles at 1 A g^(-1)with an excellent capacity retention rate.This result indicates that the addition of 1 mol-L^(-1)non-toxic sorbitol into a conventional ZnSO_(4)electrolyte can successfully protect the Zn anode interface by improving the electrochemical properties of Zn reversible deposition/decomposition,which greatly promotes its cycle performance,providing a new approach in future development of high performance aqueous Zn ion batteries.
