Nanoflakes of Ni-Co LDH and Bi₂O₃ Assembled in 3D Carbon Fiber Network for High-Performance Aqueous Rechargeable Ni/Bi Battery

For aqueous nickel/metal batteries, low energy density and poor rate properties are among the limiting factors for their applications, although they are the energy storage systems with high safety, high capacity, and low production cost. Here, we have developed a class of active materials consisting of porous nanoflakes of Ni-Co hydroxides and Bi₂O₃ that are successfully assembled on carbon substrates of carbon cloth/carbon nanofiber 3D network (CC/CNF). The combination of the porous Ni-Co hydroxides/Bi₂O₃ nanoflakes with carbon substrate of 3D network is able to provide a large surface area, excellent conductivity, and promote synergistic effects, as a result of the interaction between the active materials and the carbon matrix. With the porous Ni-Co hydroxides and Bi₂O₃ nanoflakes, the Ni/Bi battery can deliver a high capacity of ∼110 mA h g^-1 at a current density of 2 A g^-1. About 80% of its capacity (85 mA h g^-1) can be retained when the current density increases to 20 A g^-1. The full cell can also maintain 93% of the initial capacity after 1000 charge/discharge cycles, showing great potential for Ni/Bi battery.