In Situ Construction of PANI/SHG/CNT Composite Electrodes with High Mass Loading for Flexible Supercapacitors by Rapid Frozen Interfacial Polymerization

High rate performance and high mass loading are important for the practical application of flexible supercapacitors with high areal capacitance. Herein, an efficient strategy is proposed for constructing porous ternary composite electrodes by combining rapid frozen interfacial polymerization and layer-by-layer spraying. The composite electrodes consist of polyaniline (PANI), sulfonated holey graphene (SHG), and carbon nanotubes (CNTs) at a high mass loading of PANI, in which the SHG with abundant pores can provide a rapid charge transport pathway, and the CNT can improve the conductivity of the nanocomposite. More importantly, the functional groups in both carbon materials greatly enhance the protonation of PANI, and as a result, high areal capacitance, rate performance, and structural stability can be achieved even at a high mass loading of 10 mg cm^–2. The maximum areal capacitance for the PANI/SHG/CNT20 composite electrode was up to 9.84 F cm^–2 at a current density of 5 mA cm^–2 among all the composite electrodes. The assembled flexible all-solid-state supercapacitors exhibited an excellent rate capability (retains 80.4% even at a current density increased from 5 to 30 mA cm^–2) and a maximum achievable energy density of 431.93 μW h cm^–2 at a power density of 2310.48 μW cm^–2. This work presents a simple and efficient method for fabricating porous composite electrodes with high mass loading and excellent energy storage capacity.