Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low ...Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low resistance to Li dendrites seriously hinder the commercialization of SPEs.Herein,we design a bifunctional flame retardant SPE by combining hydroxyapatite(HAP)nanomaterials with Nmethyl pyrrolidone(NMP)in the PVDF-HFP matrix.The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of Li TFSI in the PVDF-HFP matrix.Consequently,the prepared SPE demonstrates superior ionic conductivity at RT,excellent fireproof properties,and strong resistance to Li dendrites.The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 m A cm^(-2),and the solid-state LiFePO_4||Li cell shows excellent capacity retention of 85.3%over 600 cycles at 0.5 C.展开更多
To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with...To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.51604089,51874110,22173066,21903058)the Natural Science Foundation of Heilongjiang Province (Grant No.YQ2021B004)Open Project of State Key Laboratory of Urban Water Resource and Environment (Grant No.QA202138)。
文摘Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low resistance to Li dendrites seriously hinder the commercialization of SPEs.Herein,we design a bifunctional flame retardant SPE by combining hydroxyapatite(HAP)nanomaterials with Nmethyl pyrrolidone(NMP)in the PVDF-HFP matrix.The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of Li TFSI in the PVDF-HFP matrix.Consequently,the prepared SPE demonstrates superior ionic conductivity at RT,excellent fireproof properties,and strong resistance to Li dendrites.The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 m A cm^(-2),and the solid-state LiFePO_4||Li cell shows excellent capacity retention of 85.3%over 600 cycles at 0.5 C.
基金This work was financially supported by the National Natural Science Foundations of China(21878061).
文摘To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.
