Due to their low thermal conductivity, non-toxicity and low cost, conductive polymer materials are potential candidates for thermoelectric applications. Here, a detailed investigation into the thermoelectric properties of P3HT films is reported. A thermoelectric power factor over 20 mW m À1 K À2 at room temperature was obtained by employing a ferric salt of triflimide (TFSI À ) anions as a dopant. Flexible films of P3HT-TFSI were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM), along with temperature-variant electrical measurements. Given the promising results obtained from ordinary P3HT films by a simple doping treatment, this work suggests the significance of the appropriate choice of dopants and/or counterions, as well as the polymers themselves.

We investigated rechargeable aluminum (Al) batteries composed of an Al negative electrode, a graphite positive electrode, and an ionic liquid (IL) electrolyte at temperatures down to -40 °C. The reversible battery discharge capacity at low temperatures could be superior to that at room temperature. In situ/operando electrochemical and synchrotron X-ray diffraction experiments combined with theoretical modeling revealed stable AlCl/graphite intercalation up to stage 3 at low temperatures, whereas intercalation was reversible up to stage 4 at room temperature (RT). The higher-degree anion/graphite intercalation at low temperatures affords rechargeable Al battery with higher discharge voltage (up to 2.5 V, a record for Al battery) and energy density. A remarkable cycle life of >20,000 cycles at a rate of 6C (10 minutes charge time) was achievable for Al battery operating at low temperatures, corresponding to a >50-year battery life if charged/discharged once daily.