Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incor...Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incorporating heteroatom strategy via one-step hydrothermal approach to adjust more than one factor of Mn-doped NiFe(oxy)hydroxide(Mn-NiFeOOH/LDH)heterojunction.Mn doping regulates heterojunction morphology(reducing nanoparticles and becoming thinner and denser nanosheets),Ni/Fe ratio and valence states(Ni^(2+),Ni^(3+),and Ni^(3+Δ))of Ni ions.The former could effectively increase surface active sites,and the latter two reduce the content of Fe in the Mnx-NiFeOOH/LDH heterojunction,en-abling more Ni^(2+)convert to Ni^(3+/3+Δ)that have higher intrinsic OER activity.As a result,the first-rank Mn-NiFeOOH/LDH with ultra-low overpotential of 185 mV@20 mA cm^(-2) and 296 mV@500 mA cm^(-2),and the improved OER performance are outdo to those of commercial RuO_(2) catalyst for OER.Moreover,the Mn-NiFeOOH/LDH affords the earliest initial potential(1.392 V vs.RHE),corresponds to a recorded low overpotential(162 mV).Based on the density functional theory(DFT),Mn dopants can alter intermedi-ate adsorption energy and effectively decrease∗OOH’s energy barrier.This research exhibits a feasible strategy to design low cost electrocatalysts and provide new possibilities for future industrialization.展开更多
Although their cost-effectiveness and intrinsic safety,aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction,Zn corrosion and passivation,and Zn dendrite formation on th...Although their cost-effectiveness and intrinsic safety,aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction,Zn corrosion and passivation,and Zn dendrite formation on the anode.Despite numerous strategies to alleviate these side reactions have been demonstrated,they can only provide limited performance improvement from a single aspect.Herein,a triple-functional additive with trace amounts,ammonium hydroxide,was demonstrated to comprehensively protect zinc anodes.The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes.Moreover,cationic NH^(4+)can preferentially adsorb on the Zn anode surface to shield the“tip effect”and homogenize the electric field.Benefitting from this comprehensive protection,dendrite-free Zn deposition and highly reversible Zn plating/stripping behaviors were realized.Besides,improved electrochemical performances can also be achieved in Zn//MnO_(2)full cells by taking the advantages of this triple-functional additive.This work provides a new strategy for stabilizing Zn anodes from a comprehensive perspective.展开更多
基金funding support by the Changsha Natural Science Foundation(grant no.kq2208023)National Natural Scientific Foundation of China(grant no.12074113).
文摘Transition metal(oxy)hydroxides are potential oxygen evolution reaction(OER)electrocatalysts;however,simultaneously modulating multiple factors to enhance their performance is a grand challenge.Here,we report an incorporating heteroatom strategy via one-step hydrothermal approach to adjust more than one factor of Mn-doped NiFe(oxy)hydroxide(Mn-NiFeOOH/LDH)heterojunction.Mn doping regulates heterojunction morphology(reducing nanoparticles and becoming thinner and denser nanosheets),Ni/Fe ratio and valence states(Ni^(2+),Ni^(3+),and Ni^(3+Δ))of Ni ions.The former could effectively increase surface active sites,and the latter two reduce the content of Fe in the Mnx-NiFeOOH/LDH heterojunction,en-abling more Ni^(2+)convert to Ni^(3+/3+Δ)that have higher intrinsic OER activity.As a result,the first-rank Mn-NiFeOOH/LDH with ultra-low overpotential of 185 mV@20 mA cm^(-2) and 296 mV@500 mA cm^(-2),and the improved OER performance are outdo to those of commercial RuO_(2) catalyst for OER.Moreover,the Mn-NiFeOOH/LDH affords the earliest initial potential(1.392 V vs.RHE),corresponds to a recorded low overpotential(162 mV).Based on the density functional theory(DFT),Mn dopants can alter intermedi-ate adsorption energy and effectively decrease∗OOH’s energy barrier.This research exhibits a feasible strategy to design low cost electrocatalysts and provide new possibilities for future industrialization.
基金supported by the National Key Research and Development Program of China(2019YFE0114400)the Guangdong Basic and Applied Basic Research Foundation(2021B1515120005)+7 种基金the National Natural Science Foundation of China(32171721)the Guangdong Basic and Applied Basic Research Foundation(2021B151512000)the Guangzhou Science and Technology Plan Project(202102020262)the State Key Laboratory of Pulp&Paper Engineering(2022C01),the State Key Laboratory of Pulp&Paper Engineering(202208)the Engineering and Physical Sciences Research Council(EPSRCEP/V027433/1EP/V027433/2EP/Y008707/1)。
文摘Although their cost-effectiveness and intrinsic safety,aqueous zinc-ion batteries suffer from notorious side reactions including hydrogen evolution reaction,Zn corrosion and passivation,and Zn dendrite formation on the anode.Despite numerous strategies to alleviate these side reactions have been demonstrated,they can only provide limited performance improvement from a single aspect.Herein,a triple-functional additive with trace amounts,ammonium hydroxide,was demonstrated to comprehensively protect zinc anodes.The results show that the shift of electrolyte pH from 4.1 to 5.2 lowers the HER potential and encourages the in situ formation of a uniform ZHS-based solid electrolyte interphase on Zn anodes.Moreover,cationic NH^(4+)can preferentially adsorb on the Zn anode surface to shield the“tip effect”and homogenize the electric field.Benefitting from this comprehensive protection,dendrite-free Zn deposition and highly reversible Zn plating/stripping behaviors were realized.Besides,improved electrochemical performances can also be achieved in Zn//MnO_(2)full cells by taking the advantages of this triple-functional additive.This work provides a new strategy for stabilizing Zn anodes from a comprehensive perspective.
