Electrochemical Performance of Pre-Modified Birch Biochar Monolith Supercapacitors by Ferric Chloride and Ferric Citrate
This study investigated the electrochemical properties of supercapacitors by pre-modifying thick birch biochar monoliths with FeCl<sub>3</sub> or C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub> solutions prior to wood pyrolysis. The pre-modification introduc...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Batteries |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2313-0105/11/2/47 |
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| Summary: | This study investigated the electrochemical properties of supercapacitors by pre-modifying thick birch biochar monoliths with FeCl<sub>3</sub> or C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub> solutions prior to wood pyrolysis. The pre-modification introduced iron species to the surface, promoting the specific surface area, charge-stored species, and surface functionalities, which enhanced the gravimetric capacitance. X-ray diffraction confirmed the successful loading of Fe<sub>3</sub>O<sub>4</sub> and Fe. SEM implied the wider distribution of iron-rich particulates and porous carbon via self-pyrolysis on the biochar surface modified with 1.0 M C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub>. Contact angle measurements demonstrated the enhanced wettability of the biochar surfaces following pre-modification, with the C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub>-modified samples exhibiting superior wettability compared to the other groups. The gravimetric capacitance of the supercapacitor was dramatically promoted and reached 210 F/g and 219 F/g, respectively, when modified with 1.0M C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub> and 1.0 M FeCl<sub>3</sub> at a 5 mA/g current density. Compared to the birch biochar modified with 1.0 M FeCl<sub>3</sub>, the 1.0 M C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub> had a higher current response peak and capacitive behavior in the CV analysis, demonstrated better ion diffusion capacity, and had lower charge-transfer resistance in the EIS results. But, a slight irreversible process on the electrode of the 1.0 M C<sub>6</sub>H<sub>5</sub>FeO<sub>7</sub> group led to a lower level of the supercapacitor capacitance retention. The results using ferric solution pre-impregnation show how iron species doping can improve capacitance behavior, providing a feasible scheme for the modification of thick biochar monolith. |
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| ISSN: | 2313-0105 |