Although ionic thermoelectric (iTE) materials can have very high thermopower, it is of great significance to develop novel methods to further improve the ionic thermopower and figure of merit (ZTi). Here, significant improvement in the thermopower and thus the ZTi value of an ionogel by cationic doping, is reported. Doping sodium dicyanamide (Na:DCA) into the ionogels of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) and 1‐ethyl‐3‐methylimidazolium dicyanamide (EMIM:DCA) that is an ionic liquid can greatly enhance the thermopower. This is attributed to the interactions between the doped Na+ cations and DCA– anions, thereby increasing the difference in the mobilities of EMIM+ cations and DCA– anions. Moreover, through the combination with the solid networks engineering by an anti‐solvent to PVDF‐HFP, the PVDF‐HFP/EMIM:DCA ionogel doped with 0.5 mol% Na+ with respect to EMIM+ exhibits an ionic thermopower of 43.8 ± 1.0 mV K–1, ionic conductivity of 19.4 ± 0.3 mS cm–1 and thermal conductivity of 0.183 W m–1 K–1 at the relative humidity of 85% and room temperature. The corresponding ZTi value thus reaches 6.1 ± 0.4, much higher than the previous ZTi records of iTE materials. These ionogels can be used in the iTE capacitors for the thermoelectric conversion.

Abundant heat is generated in household, industry and natural processes, and the majority of the heat is dissipated to environment as waste heat owing to the low heat utilization efficiency....

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Ionic thermoelectric (TE) materials such as ionic hydrogels and ionogels consisting of ionic liquid emerged as the next-generation TE materials because of their quasi-solid state and high TE properties, particularly...

Porous graphene has been recognized as a promising material for applications in electrochemical applications. Engineering the porous graphene-based hierarchical and hybrid structures is a promising way to further improve the electrochemical performances. Here, we reported a rational design of the porous graphene@Mn3O4 (PGM) structure for the applications in both the oxygen reduction reaction (ORR) and supercapacitor. Thanks to the efficient porous graphene substrate and rational decoration of Mn3O4, the catalytic performance of as-prepared PGM is comparative to that of Pt/C when used as electrocatalysts for the ORR, showing a relatively positive onset and half-wave potential (0.89 and 0.81 V) and a large diffusion-limiting current density (5.85 mA cm–2). In addition, PGM also shows good specific capacitance (208.3 F g–1), cycle stability, and rate performance when used in the supercapacitor electrodes and asymmetric device (maximum energy density of 30.1 Wh kg–1 and power density of 9500 W kg–1).

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It is of significance to develop efficient heat-to-electricity conversion technology for the sustainable development because of the abundant waste heat on earth. Waste heat can produce temperature gradient to environment,...