The rate capability and cycling stability of sodium metal batteries taking FeS_(2) or sulfur as cathode are limited due to their low reaction kinetics and severe shuttle effect.Herein,we rationally design a novel sing...The rate capability and cycling stability of sodium metal batteries taking FeS_(2) or sulfur as cathode are limited due to their low reaction kinetics and severe shuttle effect.Herein,we rationally design a novel single-atom-dispersed S_(2)-FeNC/FeS_(2) nanocluster heterojunction embedded in carbon spheres(SFNC/FeS_(2)) for the electrode material of sodium metal batteries.Interestingly,during the discharging process,the Na^(+) is inserted into FeS_(2) to generate Na_(2)S,as well as the unique electrochemical reaction between S_(2)-FeNC and Na^(+) to form Na_(2)S.Meanwhile,the FeNC can adsorb Na_(2)S and catalyze the conversion from Na_(2)S and Fe to FeS_(2) or from Na_(2)S and FeNC to S_(2)-FeNC for suppressing the shuttle effect and promoting the distinct hybrid reversible electrochemical behavior,which improves performance tremendously.Notably,the SFNC/FeS_(2) electrode delivers a specific capacity of 338.7 mAh g^(-1) after superlong 2000 cycles at a current density of 5.0 A g^(-1) and achieves a high energy density of 430.1 Wh Kg^(-1) at a current density of 0.05 A g^(-1).This work presents a novel approach to studying sodium metal batteries with hybrid behavior for excellent high energy density and cycling stability.展开更多
金属锂负极由于比容量高(3860 mAh·g^(-1))及氧化还原电位极低(-3.04 V vs.标准氢气电极(SHE)),被认为是实现高能量密度锂电池的理想负极。然而,金属锂电极与电解液反应剧烈,且锂离子在电极表面沉积不均匀容易产生枝晶,导致其循环...金属锂负极由于比容量高(3860 mAh·g^(-1))及氧化还原电位极低(-3.04 V vs.标准氢气电极(SHE)),被认为是实现高能量密度锂电池的理想负极。然而,金属锂电极与电解液反应剧烈,且锂离子在电极表面沉积不均匀容易产生枝晶,导致其循环稳定性和安全性都较差,限制了其应用推广。我们前期通过构建金属锂-碳纳米管(Li-CNT)复合结构,极大的提高了金属锂的比表面积,降低了电极电流密度,从而有效地抑制了锂枝晶的生长,提高了金属锂电极的循环稳定性和安全性能。本工作在前期工作基础上,采用简单的液相反应,利用4-氟苯乙烯(FPS)对Li-CNT进行表面修饰并进行原位聚合,得到了表面富含氟化锂(Li F)保护层的Li-CNT(FPS-Li-CNT)。该表面修饰层能够有效抑制电解液和空气对Li-CNT的侵蚀,显著的提高了LiCNT电极的界面稳定性。FPS-Li-CNT与磷酸铁锂正极(LFP)组成的LFP||FPS-Li-CNT全电池,在正负极容量配比为1:6条件下,能够稳定循环280圈,库伦效率达到97.7%。展开更多
BiFeO_(3)(BFO)是一种新型可回收光响应催化剂,但较高的光生电子/空穴对复合率和较低的量子产率限制了其实际应用。本研究通过水热法制备出还原氧化石墨烯-BFO(RGO-BFO)纳米晶复合材料,表征与测试结果表明,相比于BFO颗粒,复合材料的禁...BiFeO_(3)(BFO)是一种新型可回收光响应催化剂,但较高的光生电子/空穴对复合率和较低的量子产率限制了其实际应用。本研究通过水热法制备出还原氧化石墨烯-BFO(RGO-BFO)纳米晶复合材料,表征与测试结果表明,相比于BFO颗粒,复合材料的禁带宽度E_(g)为2.0 e V,降低约10%;40 min对亚甲基蓝吸附–催化效率接近100%,远高于BFO颗粒(28%),这主要由于复合体系中光生电子/空穴对复合率更低。通过本征磁性回收并重复利用6次后,复合材料仍保持89.1%催化效率,表现出优异催化性能。展开更多
基金financially supported by the National Natural Science Foundation of China (No. 22579095)the Beijing-Tianjin-Hebei Basic Research Cooperation Special Project (B2024204027)+2 种基金the Youth Top-notch Talent Foundation of Hebei Provincial Universities (BJK2022023)the Natural Science Foundation of Hebei Province (B2023204006)the talent training project of Hebei province (No. B20231004)。
文摘The rate capability and cycling stability of sodium metal batteries taking FeS_(2) or sulfur as cathode are limited due to their low reaction kinetics and severe shuttle effect.Herein,we rationally design a novel single-atom-dispersed S_(2)-FeNC/FeS_(2) nanocluster heterojunction embedded in carbon spheres(SFNC/FeS_(2)) for the electrode material of sodium metal batteries.Interestingly,during the discharging process,the Na^(+) is inserted into FeS_(2) to generate Na_(2)S,as well as the unique electrochemical reaction between S_(2)-FeNC and Na^(+) to form Na_(2)S.Meanwhile,the FeNC can adsorb Na_(2)S and catalyze the conversion from Na_(2)S and Fe to FeS_(2) or from Na_(2)S and FeNC to S_(2)-FeNC for suppressing the shuttle effect and promoting the distinct hybrid reversible electrochemical behavior,which improves performance tremendously.Notably,the SFNC/FeS_(2) electrode delivers a specific capacity of 338.7 mAh g^(-1) after superlong 2000 cycles at a current density of 5.0 A g^(-1) and achieves a high energy density of 430.1 Wh Kg^(-1) at a current density of 0.05 A g^(-1).This work presents a novel approach to studying sodium metal batteries with hybrid behavior for excellent high energy density and cycling stability.
文摘金属锂负极由于比容量高(3860 mAh·g^(-1))及氧化还原电位极低(-3.04 V vs.标准氢气电极(SHE)),被认为是实现高能量密度锂电池的理想负极。然而,金属锂电极与电解液反应剧烈,且锂离子在电极表面沉积不均匀容易产生枝晶,导致其循环稳定性和安全性都较差,限制了其应用推广。我们前期通过构建金属锂-碳纳米管(Li-CNT)复合结构,极大的提高了金属锂的比表面积,降低了电极电流密度,从而有效地抑制了锂枝晶的生长,提高了金属锂电极的循环稳定性和安全性能。本工作在前期工作基础上,采用简单的液相反应,利用4-氟苯乙烯(FPS)对Li-CNT进行表面修饰并进行原位聚合,得到了表面富含氟化锂(Li F)保护层的Li-CNT(FPS-Li-CNT)。该表面修饰层能够有效抑制电解液和空气对Li-CNT的侵蚀,显著的提高了LiCNT电极的界面稳定性。FPS-Li-CNT与磷酸铁锂正极(LFP)组成的LFP||FPS-Li-CNT全电池,在正负极容量配比为1:6条件下,能够稳定循环280圈,库伦效率达到97.7%。
文摘BiFeO_(3)(BFO)是一种新型可回收光响应催化剂,但较高的光生电子/空穴对复合率和较低的量子产率限制了其实际应用。本研究通过水热法制备出还原氧化石墨烯-BFO(RGO-BFO)纳米晶复合材料,表征与测试结果表明,相比于BFO颗粒,复合材料的禁带宽度E_(g)为2.0 e V,降低约10%;40 min对亚甲基蓝吸附–催化效率接近100%,远高于BFO颗粒(28%),这主要由于复合体系中光生电子/空穴对复合率更低。通过本征磁性回收并重复利用6次后,复合材料仍保持89.1%催化效率,表现出优异催化性能。
基金The project was supported by the National Natural Science Foundation of China(21625304,21733012,21773290)the “Strategic Priority Research Program” of CAS(XDA09010600)the Ministry of Science and Technology of China(2016YFA0200703)~~
