The design of supercapacitor materials with both high areal capacity (C) and high mass loading is vitally important for enhancing energy density (E). Herein, we prepared a NiCo—OH/NiCoOOH composite film consisting of NiCo—OH/NiCoOOH nanosheets on an expanded graphite paper (EGP) by using a facial anodization method. The as-prepared NiCo—OH/NiCoOOH film exhibits ultra-high C of 11 mA·h·cm⁻² at a mass loading of 165 mg·cm⁻², high rate capability of 71% and excellent cycling stability of 95% after 12000 cycles. The outstanding performance is ascribed to the low-crystalline feature of the NiCo—OH/NiCoOOH nanosheets, and the synergistic effect of the NiCo—OH and NiCoOOH phases and high conductive porous EGP. An aqueous asymmetric supercapacitor, assembled with the NiCo—OH/NiCoOOH on EGP and Fe₂O₃ on EGP as positive- and negative-electrode, respectively, shows a highest E of 3.8 mW·h·cm⁻² at a power density (P) of 4 mW·cm⁻² and a maximum P of 107 mW·cm⁻² at an E of 2.7 mW·h·cm⁻².

In this work, poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) coated silver telluride (PCAg₂Te) nanorods were prepared by a wet-chemical method using the PEDOT:PSS coated tellurium (PCTe) nanorods as the templates. Flexible PCAg₂Te nanocomposite film on polyethersulfone (PES) substrate was prepared through vacuum filtration followed by mechanical pressing process. An optimal PCAg₂Te nanocomposite film showed a maximum power factor of 143.3 μW/mK² at room temperature and 221.7 μW/mK² at 373 K. The electrical conductivity of the PCAg₂Te composite film decreased by ∼ 3.3% after bending for 1000 times around a rod with a radius of 5 mm. An eight-leg thermoelectric generator assembled with the optimal PCAg₂Te nanocomposite film generated a maximum output power and output density of 209.4 nW and 141.5 μW/cm² at a temperature gradient of 30.3 K. This work provides a facile method to prepare thermoelectric materials for flexible thermoelectric generators.