Despite promising characteristics such as high specific energy and low cost,current Li-S batteries fall short in cycle life.Improving the cycling stability of S cathodes requires immobilizing the lithium polysulfide ...Despite promising characteristics such as high specific energy and low cost,current Li-S batteries fall short in cycle life.Improving the cycling stability of S cathodes requires immobilizing the lithium polysulfide （LPS） intermediates as well as accelerating their redox kinetics.Although many materials have been explored for trapping LPS,the ability to promote LPS redox has attracted much less attention.Here,we report for the first time on transition metal phosphides as effective host materials to enhance both LPS adsorption and redox.Integrating MoP-nanoparticle-decorated carbon nanotubes with S deposited on graphene oxide,we enable Li-S battery cathodes with substantially improved cycling stability and rate capability.Capacity decay rates as low as 0.017% per cycle over 1,000 cycles can be realized.Stable and high areal capacity （〉 3 mAh＆#183;cm-2） can be achieved under high mass loading conditions.Comparable electrochemical performance can also be achieved with analogous material structures based on CoP,demonstrating the potential of metal phosphides for long-cycle Li-S batteries.展开更多
A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merge...A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0–4.3 V, Li3Nd0.08V1.92（PO4）3exhibits an initial discharge capacity of 115.8 m Ah/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51 st cycle.In addition, Li3Nd0.05V1.95（PO4）3holds at 100.4 m Ah/g after 80 cycles at 0.2 C with a capacity retention of92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92（PO4）3decreased compared with the un-doped one.展开更多
文摘Despite promising characteristics such as high specific energy and low cost,current Li-S batteries fall short in cycle life.Improving the cycling stability of S cathodes requires immobilizing the lithium polysulfide （LPS） intermediates as well as accelerating their redox kinetics.Although many materials have been explored for trapping LPS,the ability to promote LPS redox has attracted much less attention.Here,we report for the first time on transition metal phosphides as effective host materials to enhance both LPS adsorption and redox.Integrating MoP-nanoparticle-decorated carbon nanotubes with S deposited on graphene oxide,we enable Li-S battery cathodes with substantially improved cycling stability and rate capability.Capacity decay rates as low as 0.017% per cycle over 1,000 cycles can be realized.Stable and high areal capacity （〉 3 mAh＆#183;cm-2） can be achieved under high mass loading conditions.Comparable electrochemical performance can also be achieved with analogous material structures based on CoP,demonstrating the potential of metal phosphides for long-cycle Li-S batteries.
基金supported by the National Key Program for Basic Research of China(No.2009CB220100)National High-tech 863Key Program(No.2011AA11A235)Basic Research Fund of Beijing Institute of Technology(No.3100012211111)
文摘A series of Nd^3＋-doped LiNdxV2-x（PO4）3（x = 0.00, 0.02, 0.05, 0.08 or 0.1） composites are synthesized by the rheological phase reaction method. The XRD results indicate that Nd3＋ions have been successfully merged into a lattice structure. Doped samples show good electrochemical performance in high discharge rate and long cycle. In the potential range of 3.0–4.3 V, Li3Nd0.08V1.92（PO4）3exhibits an initial discharge capacity of 115.8 m Ah/g at 0.2 C and retain 80.86% of capacity retention at 2 C in the 51 st cycle.In addition, Li3Nd0.05V1.95（PO4）3holds at 100.4 m Ah/g after 80 cycles at 0.2 C with a capacity retention of92.4%. Finally, the CV test proves that the potential polarization of Li3Nd0.08V1.92（PO4）3decreased compared with the un-doped one.
