Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))an...Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.展开更多
The carbon materials as anode electrodes have been widely studied for potassium ion batteries(PIBs).However,the large size of potassium ions prevents their intercalation/deintercalation,resulting in poor storage behav...The carbon materials as anode electrodes have been widely studied for potassium ion batteries(PIBs).However,the large size of potassium ions prevents their intercalation/deintercalation,resulting in poor storage behaviors.Herein,a novel design of N/S codoped hierarchical carbonaceous fibers(NSHCF)formed from nanosheets self-assembled by catalyzing Aspergillus niger with Sn is reported.The asprepared NSHCF at 600℃(NSHCF-600)exhibits a high reversible capacity of 345.4 m Ah g^(-1) at 0.1 A g^(-1) after 100 cycles and an excellent rate performance of 124.5 m Ah g^(-1) at 2 A g^(-1).The excellent potassium storage performance can be ascribed to the N/S dual-doping,which enlarges interlayer spacing(0.404 nm)and introduces more defects.The larger interlayer spacing and higher pyridinic N active sites can promote K ions diffusion and storage.In addition,the ex situ transmission electron microscopy reveals the high reversibility of potassiation/depotassiation process and structural stability.展开更多
先利用羟基化多壁碳纳米管(MWCNTs-OH)与纸纤维制备了复合纤维纸(MWCNTs-OHP),然后将该复合纤维纸夹在两层PP隔膜之间组装三明治结构隔膜(PP@MWCNTs-OHP@PP)并应用于锂硫电池.利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱...先利用羟基化多壁碳纳米管(MWCNTs-OH)与纸纤维制备了复合纤维纸(MWCNTs-OHP),然后将该复合纤维纸夹在两层PP隔膜之间组装三明治结构隔膜(PP@MWCNTs-OHP@PP)并应用于锂硫电池.利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱和元素能谱分析(EDS)等对材料进行结构和性能表征.电化学测试结果表明,PP@MWCNTs-OHP@PP三明治隔膜有效提高了锂硫电池的性能.在0.1C倍率下,电池首次放电比容量达到1532 m A·h/g,活性物质的利用率达到91.5%.在1C倍率下充放电循环500周后,放电比容量依然维持516 m A·h/g,每周循环衰减率为0.028%,库仑效率保持在96.4%以上.充放电倍率从3C减小到0.1C后,放电比容量从336 m A·h/g恢复到820 m A·h/g,显示出极佳的倍率性能.展开更多
基金partly funded by the German Research Foundation(DFG)under Project ID 390874152(POLiS Cluster of Excellence,EXC2154)。
文摘Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.
基金financial support from the National Natural Science Foundation of China(NSFC Grant No.21571080)the Project 2019JLP-04 supported by Joint Foundation of ShaanxiXi’an Science and Technology Project of China(201805037YD15CG21(20))。
文摘The carbon materials as anode electrodes have been widely studied for potassium ion batteries(PIBs).However,the large size of potassium ions prevents their intercalation/deintercalation,resulting in poor storage behaviors.Herein,a novel design of N/S codoped hierarchical carbonaceous fibers(NSHCF)formed from nanosheets self-assembled by catalyzing Aspergillus niger with Sn is reported.The asprepared NSHCF at 600℃(NSHCF-600)exhibits a high reversible capacity of 345.4 m Ah g^(-1) at 0.1 A g^(-1) after 100 cycles and an excellent rate performance of 124.5 m Ah g^(-1) at 2 A g^(-1).The excellent potassium storage performance can be ascribed to the N/S dual-doping,which enlarges interlayer spacing(0.404 nm)and introduces more defects.The larger interlayer spacing and higher pyridinic N active sites can promote K ions diffusion and storage.In addition,the ex situ transmission electron microscopy reveals the high reversibility of potassiation/depotassiation process and structural stability.
文摘先利用羟基化多壁碳纳米管(MWCNTs-OH)与纸纤维制备了复合纤维纸(MWCNTs-OHP),然后将该复合纤维纸夹在两层PP隔膜之间组装三明治结构隔膜(PP@MWCNTs-OHP@PP)并应用于锂硫电池.利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱和元素能谱分析(EDS)等对材料进行结构和性能表征.电化学测试结果表明,PP@MWCNTs-OHP@PP三明治隔膜有效提高了锂硫电池的性能.在0.1C倍率下,电池首次放电比容量达到1532 m A·h/g,活性物质的利用率达到91.5%.在1C倍率下充放电循环500周后,放电比容量依然维持516 m A·h/g,每周循环衰减率为0.028%,库仑效率保持在96.4%以上.充放电倍率从3C减小到0.1C后,放电比容量从336 m A·h/g恢复到820 m A·h/g,显示出极佳的倍率性能.
