Tellurium (Te) is an ideal electrode for potassium ion batteries (PIBs) owing to its excellent electronic conductivity and high volumetric capacity.However,the Te electrode is prone to capacity fading as the shuttle e...Tellurium (Te) is an ideal electrode for potassium ion batteries (PIBs) owing to its excellent electronic conductivity and high volumetric capacity.However,the Te electrode is prone to capacity fading as the shuttle effect.To address this challenge,we propose molecular regulated Se–Te solid solutions on N-doped porous carbon as the PIBs electrode.After optimizing the Se content in Se–Te solid solutions,the resultant SeTe_(6.8) on N-doped porous carbon (SeTe_(6.8)@C) delivered a capacity of over 400 mAh g^(-1) with a flat plateau of 1.0 V at 500 m A g^(-1).It also achieved a superiorly long cycle life,running for more than 1600 cycles (over 7 months with 0.015%degeneration per cycle) at 100 mA g^(-1) and excellent rate performance (179.9 mAh g^(-1) at 10000 mA g^(-1)).This remarkable electrochemical energy storage of the Te electorde likely arises from suppression of the shuttle effect after doping the Te with strongly electronegative Se atoms (forming K_(s)Te_(3) which is not easily soluble in electrolyte).This study presents a fresh approach for designing and developing ultra-stable Te-based electrodes for PIBs and beyond.展开更多
In December 2016,with the change of President Uzbekistan,its policies and systems have undergone tremendous changes.This article will focus on the specific content of FDI system,tax policy and exchange rate policy in ...In December 2016,with the change of President Uzbekistan,its policies and systems have undergone tremendous changes.This article will focus on the specific content of FDI system,tax policy and exchange rate policy in Uzbekistan's economic reform.Taking the“Ohangaron Green City”project and the trade volume between Xinjiang and Central Asia as an example,this paper analyzes its positive impact on China-Uzbekistan cooperation and China-Uzbekistan in terms of prospects.展开更多
Polyoxometalates modified with complex cations have attracted increasing attention because of the fascinating properties and the controllable structures.By adjusting the synthesis conditions,four new terpyridine compl...Polyoxometalates modified with complex cations have attracted increasing attention because of the fascinating properties and the controllable structures.By adjusting the synthesis conditions,four new terpyridine complexes based hybrid POMs,[(TPY-H)CuCl]_(4)[W_(10)O_(32)]·2DMF·2H_(2)O(1),[(TPY-H)Cu(DMSO)(H_(2)O)]_(2)[W_(10)O_(32)]·2H_(2)O(2),[(TPY-H)_(2)Cu]_(2)[W_(10)O_(32)]·6DMSO·8H_(2)O(3) and[(TPY-Br)CuCl(DMSO)(H_(2)O)]_(2)[(TPY-Br)CuCl]_(2)[W_(10)O_(32)]·2DMSO·4H_(2)O(4),were prepared by using‘one-pot’method.Sing-crystal X-ray diffraction analyses,infrared radiation,etc.,revealed the structural composition of compounds 1—4,which indicates that synthesis conditions have a directional regulatory effect on the compounds synthesis.Thioether oxidation catalytic reactions show 1—4 have good catalytic activities,and powder X-ray diffraction and thermogravimetry analysis show 1—4 have superduper catalytic stability.Moreover,4 has better catalytic activity because of the different structure of terpyridine complexes.Therefore,a possible mechanism of dual-site catalysis by both cations and anions is proposed.展开更多
As the key to optimizing potassium ion batteries’(PIBs)performance,the development of high capacity potassium anode is the footstone.Here,through a one-step solvothermal method,uniformly dispersed SbVO4 nanoparticles...As the key to optimizing potassium ion batteries’(PIBs)performance,the development of high capacity potassium anode is the footstone.Here,through a one-step solvothermal method,uniformly dispersed SbVO4 nanoparticles on the reduced graphene oxide nanosheets(SbVO4@RGO)were synthesized and used as PIBs anodes.SbVO4@RGO anode shows high capacity due to alloying and conversion reactions occur simultaneously in the cyclic process.The anode delivers a capacity as high as 447.9 mAh g^-1 at 100 mA g^-1.Besides,a cycling life of 500 cycles with small average capacity decay rate(only 0.106%per cycle)is also revealed.It was found in the initial discharge process,SbVO4 transforms into Sb and K3VO4.And in the following cycle Sb and K3VO4 simultaneously react with K+via the alloying/de-alloying and conversion reaction,respectively.The present study of SbVO4@RGO may provide insight for high performance alloying-based/conversion-based potassium anodes.展开更多
基金inancially supported by National Nature Science Foundation of China (U20A20247 and 51922038)Hunan Natural Science Foundation (2019JJ40031)+1 种基金Open Fund program for University Innovation Platform of Hunan Province (20K026)the Fundamental Research Funds for the Central Universities。
文摘Tellurium (Te) is an ideal electrode for potassium ion batteries (PIBs) owing to its excellent electronic conductivity and high volumetric capacity.However,the Te electrode is prone to capacity fading as the shuttle effect.To address this challenge,we propose molecular regulated Se–Te solid solutions on N-doped porous carbon as the PIBs electrode.After optimizing the Se content in Se–Te solid solutions,the resultant SeTe_(6.8) on N-doped porous carbon (SeTe_(6.8)@C) delivered a capacity of over 400 mAh g^(-1) with a flat plateau of 1.0 V at 500 m A g^(-1).It also achieved a superiorly long cycle life,running for more than 1600 cycles (over 7 months with 0.015%degeneration per cycle) at 100 mA g^(-1) and excellent rate performance (179.9 mAh g^(-1) at 10000 mA g^(-1)).This remarkable electrochemical energy storage of the Te electorde likely arises from suppression of the shuttle effect after doping the Te with strongly electronegative Se atoms (forming K_(s)Te_(3) which is not easily soluble in electrolyte).This study presents a fresh approach for designing and developing ultra-stable Te-based electrodes for PIBs and beyond.
文摘In December 2016,with the change of President Uzbekistan,its policies and systems have undergone tremendous changes.This article will focus on the specific content of FDI system,tax policy and exchange rate policy in Uzbekistan's economic reform.Taking the“Ohangaron Green City”project and the trade volume between Xinjiang and Central Asia as an example,this paper analyzes its positive impact on China-Uzbekistan cooperation and China-Uzbekistan in terms of prospects.
基金the support from the Project Foundation of Hunan Provincial Education Department(21C1642,22B0641,21B0584)the Research project of Changsha Normal University(XJYB202103)+1 种基金the Natural Science Foundation of Hunan Province(2023JJ40235)the National Natural Science Foundation of China(22204050).
文摘Polyoxometalates modified with complex cations have attracted increasing attention because of the fascinating properties and the controllable structures.By adjusting the synthesis conditions,four new terpyridine complexes based hybrid POMs,[(TPY-H)CuCl]_(4)[W_(10)O_(32)]·2DMF·2H_(2)O(1),[(TPY-H)Cu(DMSO)(H_(2)O)]_(2)[W_(10)O_(32)]·2H_(2)O(2),[(TPY-H)_(2)Cu]_(2)[W_(10)O_(32)]·6DMSO·8H_(2)O(3) and[(TPY-Br)CuCl(DMSO)(H_(2)O)]_(2)[(TPY-Br)CuCl]_(2)[W_(10)O_(32)]·2DMSO·4H_(2)O(4),were prepared by using‘one-pot’method.Sing-crystal X-ray diffraction analyses,infrared radiation,etc.,revealed the structural composition of compounds 1—4,which indicates that synthesis conditions have a directional regulatory effect on the compounds synthesis.Thioether oxidation catalytic reactions show 1—4 have good catalytic activities,and powder X-ray diffraction and thermogravimetry analysis show 1—4 have superduper catalytic stability.Moreover,4 has better catalytic activity because of the different structure of terpyridine complexes.Therefore,a possible mechanism of dual-site catalysis by both cations and anions is proposed.
基金the National Natural Science Foundation of China(51922038,51672078)Hunan Outstanding Youth Talents(2019JJ20005),Hunan Provincial Natural Science Foundation of China(2019JJ40031)Fundamental Research Funds for the Central Universities。
文摘As the key to optimizing potassium ion batteries’(PIBs)performance,the development of high capacity potassium anode is the footstone.Here,through a one-step solvothermal method,uniformly dispersed SbVO4 nanoparticles on the reduced graphene oxide nanosheets(SbVO4@RGO)were synthesized and used as PIBs anodes.SbVO4@RGO anode shows high capacity due to alloying and conversion reactions occur simultaneously in the cyclic process.The anode delivers a capacity as high as 447.9 mAh g^-1 at 100 mA g^-1.Besides,a cycling life of 500 cycles with small average capacity decay rate(only 0.106%per cycle)is also revealed.It was found in the initial discharge process,SbVO4 transforms into Sb and K3VO4.And in the following cycle Sb and K3VO4 simultaneously react with K+via the alloying/de-alloying and conversion reaction,respectively.The present study of SbVO4@RGO may provide insight for high performance alloying-based/conversion-based potassium anodes.
