Nanoribbons and nanoscrolls intertwined three-dimensional vanadium oxide hydrogels for high-rate lithium storage at high mass loading level

Ultrathin layered nanomaterials show promising advantages to promote the Li+ diffusion kinetics, however, the self-aggregation/stacking of nanomaterials lead to large capacity loss and limited rate capability, which urgently needs to be addressed. Herein, we report a three-dimensional (3D) novel vanadium oxide (H2V3O8) hydrogel nanostructure composed of intertwined ultrathin nanoribbons and self-coiled nanoscrolls, synthesized by a universal modified liquid exfoliation method. The hydrogels display largely enhanced rate capability and cycling stability, compared to those of the pure nanowires and nanoribbons. Based on the geometrical features of hydrogels, the intertwined hydrogels/carbon nanotubes (CNTs) flexible film is fabricated and delivers remarkable lithium storage performance: a high capacity of 310 mA h g−1 at 0.1 A g−1, excellent rate capability (145 mA h g−1 at 12 A g−1) and stable cycling performance. Moreover, at a high mass loading up to 13 mg cm−2, the hydrogels/CNTs film delivers an area capacity ~ 2.7 mA h cm−2 (at 0.91 mA cm−2), high rate capability (an area capacity of 1.16 mA h cm−2 at 18.2 mA cm−2). The scalable hydrogels/CNTs films provide a promising route towards high performance flexible electrodes at high mass loading.