Graphene nanoscrolls-wrapped oxygen-deficient ZnSb2O6-x nanospheres for enhanced lithium-ion storage

Although polyantimonic acid (PAA, H2Sb2O6 center dot nH(2)O) possesses a high theoretical specific capacity for lithium-ion storage, its development is hindered by ultralow intrinsic electrical conductivity (similar to 10(-10) S cm(-1)). In addition, the existence of proton/crystal water and large volume change during electrochemical reaction will impair its cycling stability. Here, oxygen-deficient zinc antimonate (ZnSb2O6-x) nanospheres were designed and synthesized by a facile precipitation-calcination method and then wrapped/confined in 1D graphene nanoscrolls (GS) through graphene self-scrolling strategy. The change from acid to salt can not only endow zinc antimonate with a higher electrical conductivity (similar to 1.9 x 10(-3) S cm(-1)) but also remove the proton/crystal water. The encapsulation of GS can accommodate the volume expansion of internal ZnSb2O6-x nanospheres, prevent the loss of active species and further accelerate the transport of electrons (23 S cm(-1)). Therefore, the resultant ZnSb2O6-x@GS shows high reversible capacity (755 mAh g(-1) at 0.1 A g(-1)), good rate capability (401 and 331 mAh g(-1) at 5 and 10 A g(-1)), and long cycling performance (727 mAh g(-1) after 800 cycles at 1 A g(-1)). These results exhibit the application potential of the ZnSb2O6-x@GS anode material and prove the effectiveness of the composition and structure design. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

By encapsulating oxygen-deficient zinc antimonate in graphene nanoscrolls, its conductivity is improved and cycling stability is enhanced, showing the potential application as a high-performance anode material for lithium-ion batteries.