In Situ Intercalation of Bismuth into 3D Reduced Graphene Oxide Scaffolds for High Capacity and Long Cycle-Life Energy Storage.

Metal anodes, such as zinc and bismuth have been regarded as ideal materials for aqueous batteries due to high gravimetrical capacity, high abundance, low toxicity, and intrinsic safety. However, their translation into practical applications are hindered by the low mass loading (≈1 mg cm-2 ) of active materials. Here, the multiscale integrated structural engineering of 3D scaffold and active material, i.e., bismuth is in situ intercalated in reduced graphene oxide (rGO) wall of network, are reported. Tailoring the rapid charge transport on rGO 3D network and facile access to nano- and microscale bismuth, the rGO/Bi hybrid anode shows high utilization efficiency of 91.4% at effective high load density of ≈40 mg cm-2 , high areal capacity of 3.51 mAh cm-2 at the current density of 2 mA cm-2 and high reversibility of >10 000 cycles. The resulting Ni-Bi full battery exhibits high areal capacity of 3.13 mAh cm-2 at the current density of 2 mA cm-2 , far outperforming the other counterpart batteries. It represents a general and efficient strategy in enhancing the battery performance by designing hierarchically networked structure.