Perovskite SrVO_(3) has been investigated as a promising lithium storage anode where the V cation plays the role of the redox center,combining excellent cycle stability and safe operating potential versus Li metal pla...Perovskite SrVO_(3) has been investigated as a promising lithium storage anode where the V cation plays the role of the redox center,combining excellent cycle stability and safe operating potential versus Li metal plating,with limited capacity.Here,we demonstrate the possibility to boost the lithium storage properties,by reducing the non-redox active Sr cation content and fine-tuning the O anion vacancies while maintaining a non-stoichiometric Sr_(x)VO_(3-δ) perovskite structure.Theoretical investigations suggest that Sr vacancy can work as favorable Li^(+) storage sites and preferential transport channels for guest Li^(+) ions,contributing to the increased specific capacity and rate performance.In contrast,inducing O anion vacancy in Sr_(x)VO_(3-δ) can improve rate performance while compromising the specific capacity.Our experimental results confirm the enhancement of specific capacities by fine adjusting the Sr and O vacancies,with a maximum capacity of 444 mAh g^(-1) achieved with Sr_(0.63)VO_(3-δ),which is a 37%increase versus stoichiometric SrVO_(3).Although rich defects have been induced,Sr_(x)VO_(3-δ) electrodes maintain a stable perovskite structure during cycling versus a LiFePO_(4) cathode,and the full-cell could achieve more than 6000 discharge/charge cycles with 80%capacity retention.This result highlights the possibility to use the cation defective-based engineering approach to design high-capacity perovskite oxide anode materials.展开更多
Tin perovskite solar cells(TPSCs)are promising for lead-free perovskite solar cells(PSCs)and have led to extensive research;however,the poor crystallinity and chemical stability of tin perovskites are two issues that ...Tin perovskite solar cells(TPSCs)are promising for lead-free perovskite solar cells(PSCs)and have led to extensive research;however,the poor crystallinity and chemical stability of tin perovskites are two issues that prevent stable TPSCs.In this study,we outline a new process that addresses these issues by using tin(II)acetate(Sn(Ac)2)in place of the conventional SnF2 precursor additive.Compared with SnF2,Sn(Ac)2 improves the crystallinity and stability of tin perovskite with fewer defects and better charge extraction.Using this process,we developed a device that has a higher external quantum efficiency for charge extraction compared with the control devices and a power conversion efficiency of 9.93%,which maintained more than 90%of its initial efficiency after 1000 h operation at the maximum power point under standard AM 1.5G solar illumination.展开更多
基金supported by the National Double First-Class Universities Construction Grant of Sichuan University(2020SCUNG201)the National Natural Science Foundation of China (52072252 and 51902215)+4 种基金Fundamental Research Funds for the Central UniversitiesChina (YJ201886)State Key Laboratory of Polymer Materials EngineeringChina(sklpme2021-JX-01)the Agence Nationale de la Recherche (Labex STORE-EX),France for financial support
文摘Perovskite SrVO_(3) has been investigated as a promising lithium storage anode where the V cation plays the role of the redox center,combining excellent cycle stability and safe operating potential versus Li metal plating,with limited capacity.Here,we demonstrate the possibility to boost the lithium storage properties,by reducing the non-redox active Sr cation content and fine-tuning the O anion vacancies while maintaining a non-stoichiometric Sr_(x)VO_(3-δ) perovskite structure.Theoretical investigations suggest that Sr vacancy can work as favorable Li^(+) storage sites and preferential transport channels for guest Li^(+) ions,contributing to the increased specific capacity and rate performance.In contrast,inducing O anion vacancy in Sr_(x)VO_(3-δ) can improve rate performance while compromising the specific capacity.Our experimental results confirm the enhancement of specific capacities by fine adjusting the Sr and O vacancies,with a maximum capacity of 444 mAh g^(-1) achieved with Sr_(0.63)VO_(3-δ),which is a 37%increase versus stoichiometric SrVO_(3).Although rich defects have been induced,Sr_(x)VO_(3-δ) electrodes maintain a stable perovskite structure during cycling versus a LiFePO_(4) cathode,and the full-cell could achieve more than 6000 discharge/charge cycles with 80%capacity retention.This result highlights the possibility to use the cation defective-based engineering approach to design high-capacity perovskite oxide anode materials.
基金the National Natural Science Foundation of China(11834011 and 11911530142)。
文摘Tin perovskite solar cells(TPSCs)are promising for lead-free perovskite solar cells(PSCs)and have led to extensive research;however,the poor crystallinity and chemical stability of tin perovskites are two issues that prevent stable TPSCs.In this study,we outline a new process that addresses these issues by using tin(II)acetate(Sn(Ac)2)in place of the conventional SnF2 precursor additive.Compared with SnF2,Sn(Ac)2 improves the crystallinity and stability of tin perovskite with fewer defects and better charge extraction.Using this process,we developed a device that has a higher external quantum efficiency for charge extraction compared with the control devices and a power conversion efficiency of 9.93%,which maintained more than 90%of its initial efficiency after 1000 h operation at the maximum power point under standard AM 1.5G solar illumination.
