Light-weight and low-cost carbon nanofiber collector used for various binder-free cathodes of sodium-ion batteries

Sodium-ion batteries, as an energy storage device with abundant resources and low costs is on the way to be commercialized. As a key component, the compact aluminum (Al) foil current collector occupies a large proportion of the electrode, which would reduce the energy density. Here, a porous carbon nanofiber current collector was prepared accompanying by developing a novel way to load all kinds of positive materials. Its one-dimensional structure with high aspect ratio is beneficial to electron transfer, and the cross-linked network structure can hold active components well. The electrostatic absorption between carbon nanofiber current collector and conductive agent, CNTs as well as van Der Waals forces between CNTs and Na 0.7 MnO 2.05 (NMO) realizes a self-standing metal oxide cathode without using polymer binder. At the same active component loaded, the carbon fiber current collector shows better capacity retention and cycle life (200 cycles life with 85% capacity retention) than Al foil current collector. This work provides an idea for developing a light-weight, low-cost current collector and a way to load active component without binder. • Developing a novel loading way for active materials without binders. • The porous carbon fiber current collector reduces the weight of the electrode. • The carbon fiber current collector improves the electrochemical performance of batteries.