An amorphous niobium polysulfide based nanocomposite enables ultrastable all-solid-state lithium batteries†
Abstract
Transition metal sulfide cathodes have attracted much attention in all-solid-state lithium batteries due to their high theoretical specific capacity. However, the low ionic/electronic conductivities and volume expansion of sulfide cathodes are great challenges for their practical application. In this work, an amorphous NbS4.5 (a-NbS4.5) based nanocomposite cathode is designed for all-solid-state lithium batteries. Combining with Super P, the electronic conductivity of a-NbS4.5 is improved and volume changes are suppressed. Further coupling with Li7P3S11 solid electrolyte, both interfacial contact and ionic conductivity are enhanced. As a result, the all-solid-state batteries using the a-NbS4.5/20%Super P@15%Li7P3S11 cathode exhibit high reversible capacity and excellent cycling stability, delivering an initial discharge capacity of 975.7 mA h g−1 at a current density of 0.1 A g−1 and a reversible capacity of 464.8 mA h g−1 after 2500 cycles at 0.5 A g−1. These results demonstrated that the a-NbS4.5/20%Super P@15%Li7P3S11 nanocomposite is a promising potential cathode for all-solid-state batteries.