Flexible and free-standing porous electrode fabricated with sacrificial polymeric chaperone PAN/TPU binder and design of flexible energy storage device

Polyacrylonitrile (PAN) and thermoplastic polyurethane (TPU) were used as sacrificial polymer chaperone adhesives to prepare porous flexible free-standing electrodes. The prepared electrode has excellent flexibility, and the surface porous structure realizes porous channels for electrolyte, which fully ensures the infiltration of electrolyte in the electrode, so that the electrochemical performance is comparable to that of a conventional coated electrode. Ketjen black carbon (abbreviated KB) and carbon nanofibers (CNF) offer a good electronic conductive network in this electrode, while PAN forms a free-standing skeleton and TPU provides flexible components and sacrificial templates. The method utilized is universal for commercial electrode materials and has excellent practical value. The prepared electrode has an area density of more than 10 mg cm⁻² (20 mg cm^-2 can be achieved by adjusting the slurry ratio), which is equivalent to the area density of current commercial coating electrodes. The electrode with NCM523 as active material exhibits the same electrochemical performance as traditional coated electrodes, deliver a high charge capacity 150.0 mAh g⁻¹ (10.0 mg cm⁻²) after 100 cycles at 0.2 C.