ⅢThe superior adaptability of Prussian blue analogues(PBAs)in interacting with potassium ions has shifted research focus toward their potential application as cathodes of potassium-ion batteries(PIBs).The large inter...ⅢThe superior adaptability of Prussian blue analogues(PBAs)in interacting with potassium ions has shifted research focus toward their potential application as cathodes of potassium-ion batteries(PIBs).The large interstitial space formed between metal ions and–C≡N–in PBAs can accommodate large-radius K^(+).However,the rapid nucleation in the co-precipitation synthesis process of PBAs induces many lattice defects of[M(CN)_(6)]^(4-)vacancies(V_([M–C≡N])),interstitial and coordinated H_(2)O molecules,which will directly lead to performance degradation.Moreover,originating from various transition metal elements in low/high-spin electron configuration states,PBAs exhibit diverse electrochemical behaviors,such as low reaction kinetics of low-spin iron(Ⅱ),Jahn-Teller distortion and dissolution of manganese(Ⅲ),and electrochemical inertness of nickel(Ⅱ)and copper(Ⅱ).Here,we summarize recently reported structures and properties of PBAs,classifying them based on the types of transition metals(iron,cobalt,manganese,copper,nickel)employed.Advanced synthesis strategies,including control engineering of crystallinity based on H_(2)O molecules and V_([M–C≡N]),were discussed.Also,the approaches for enhancing the electrochemical performance of PBAs were highlighted.Finally,the challenges and prospects towards the future development of PBAs are put forward.The review is expected to provide technical and theoretical support for the design of high-performance PBAs.展开更多
Sodium-ion batteries(SIBs)have emerged as a promising alternative to lithium-ion batteries due to the abundance of sodium and their cost-effectiveness.However,their performance under extreme temperature conditions(bot...Sodium-ion batteries(SIBs)have emerged as a promising alternative to lithium-ion batteries due to the abundance of sodium and their cost-effectiveness.However,their performance under extreme temperature conditions(both low and high temperatures)remains a critical challenge for practical applications.At low temperatures,sluggish ion diffusion and electrolyte freezing limit electrochemical performance,while high temperatures accelerate degradation and safety risks.This review comprehensively summarizes recent research progress on SIBs under extreme temperature environments,focusing on key materials,including electrodes,and electrolytes.Advanced approaches such as electrolyte optimization(e.g.,low-freezing-point solvents,high-concentration electrolytes)and robust electrode design(e.g.,nanostructure engineering)are discussed to enhance temperature resilience.By addressing these challenges,SIBs can achieve broader applicability in extreme climates,from polar regions to deserts,paving the way for sustainable energy storage solutions.展开更多
China's 2004 value-added tax(VAT)pilot reform in the Northeast region,which changed the VAT from production type to consumption type,introduced a sizable tax credit for fixed investment in manufacturing industries...China's 2004 value-added tax(VAT)pilot reform in the Northeast region,which changed the VAT from production type to consumption type,introduced a sizable tax credit for fixed investment in manufacturing industries,leading to more investment and higher productivity at firm level.This paper,however,uses difference-in-difference estimation and finds a negative structural effect;that is,the VAT pilot reform leads to a reduction in the export sophistication of Northeast cities relative to other cities in China,and the results hold for a battery of robustness checks.It is found that resources are reallocated towards less-sophisticated industries.As the products with higher export sophistication are more skill and research and development(R&D)intensive,the shortfalls of skilled labor and R&D spending hinder the upgrading process.With a new round of revitalization plans in the Northeast,policymakers should be cautious with similar structural effects and focus on increasing skilled labor supply and R&D investment.展开更多
基金financially supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(No.52021004)National Key Research and Development Program of China(2022YFB3803300)+2 种基金National Natural Science Foundation of China(62474026 and 62074022)Natural Science Foundation of Chongqing(CSTB2024NSCQ-MSX1215,cstc2021jcyj-jqX0015 and CSTB2022NSCQ-MSX1183)the Youth Talent Support Program of Chongqing(CQYC2021059206).
文摘ⅢThe superior adaptability of Prussian blue analogues(PBAs)in interacting with potassium ions has shifted research focus toward their potential application as cathodes of potassium-ion batteries(PIBs).The large interstitial space formed between metal ions and–C≡N–in PBAs can accommodate large-radius K^(+).However,the rapid nucleation in the co-precipitation synthesis process of PBAs induces many lattice defects of[M(CN)_(6)]^(4-)vacancies(V_([M–C≡N])),interstitial and coordinated H_(2)O molecules,which will directly lead to performance degradation.Moreover,originating from various transition metal elements in low/high-spin electron configuration states,PBAs exhibit diverse electrochemical behaviors,such as low reaction kinetics of low-spin iron(Ⅱ),Jahn-Teller distortion and dissolution of manganese(Ⅲ),and electrochemical inertness of nickel(Ⅱ)and copper(Ⅱ).Here,we summarize recently reported structures and properties of PBAs,classifying them based on the types of transition metals(iron,cobalt,manganese,copper,nickel)employed.Advanced synthesis strategies,including control engineering of crystallinity based on H_(2)O molecules and V_([M–C≡N]),were discussed.Also,the approaches for enhancing the electrochemical performance of PBAs were highlighted.Finally,the challenges and prospects towards the future development of PBAs are put forward.The review is expected to provide technical and theoretical support for the design of high-performance PBAs.
基金supported by National Key Research and Development Program of China(No.2024YFE0209200)Innovation Project of China Southern Power Grid Energy Storage Co.,Ltd.(No.029000KC23070008).
文摘Sodium-ion batteries(SIBs)have emerged as a promising alternative to lithium-ion batteries due to the abundance of sodium and their cost-effectiveness.However,their performance under extreme temperature conditions(both low and high temperatures)remains a critical challenge for practical applications.At low temperatures,sluggish ion diffusion and electrolyte freezing limit electrochemical performance,while high temperatures accelerate degradation and safety risks.This review comprehensively summarizes recent research progress on SIBs under extreme temperature environments,focusing on key materials,including electrodes,and electrolytes.Advanced approaches such as electrolyte optimization(e.g.,low-freezing-point solvents,high-concentration electrolytes)and robust electrode design(e.g.,nanostructure engineering)are discussed to enhance temperature resilience.By addressing these challenges,SIBs can achieve broader applicability in extreme climates,from polar regions to deserts,paving the way for sustainable energy storage solutions.
基金supported by the National Natural Science Foundation of China(Nos.71803159,71703130)Ministry of Education Project of Humanities and Social Sciences(No.19YJC790061)the Fundamental Research Funds for the Central Universities(No.JBK2007086).
文摘China's 2004 value-added tax(VAT)pilot reform in the Northeast region,which changed the VAT from production type to consumption type,introduced a sizable tax credit for fixed investment in manufacturing industries,leading to more investment and higher productivity at firm level.This paper,however,uses difference-in-difference estimation and finds a negative structural effect;that is,the VAT pilot reform leads to a reduction in the export sophistication of Northeast cities relative to other cities in China,and the results hold for a battery of robustness checks.It is found that resources are reallocated towards less-sophisticated industries.As the products with higher export sophistication are more skill and research and development(R&D)intensive,the shortfalls of skilled labor and R&D spending hinder the upgrading process.With a new round of revitalization plans in the Northeast,policymakers should be cautious with similar structural effects and focus on increasing skilled labor supply and R&D investment.
