Bamboo Tar-Derived Porous Carbon for Supercapacitors with Excellent Performance through Cross-Linking with Phytic Acid

Bamboo tar (BT) is the main byproduct of bamboo charcoal production, containing nearly 100 types of organic compounds, and is always disposed of as waste. An important utilization approach of BT is the synthesis of carbon materials, but a low carbon yield is readily obtained because it contains a number of volatile phenolic compounds. In this work, BT was used as a starting material for the preparation of the carbon electrodes of supercapacitors (SCs). To increase the carbon yield, BT was used for the first time to react with phytic acid (PA) to generate cross-linking macromolecules prior to carbonization, which significantly increased the carbonization yield from 17.9% for BT to 49.1% for the mixture of PA and BT. The IR spectroscopy results revealed that a new P–O–C bond appeared during the pyrolysis process, indicating the occurrence of the cross-linking reaction between PA and phenolic compounds by esterification reactions. The cross-linking reactions between some volatile aromatics and PA to produce macromolecules improve their thermal stability, which greatly increases the carbon yield (29.8–49.1%), as evidenced by the TG/DTG results. The assembled zinc-ion hybrid supercapacitors (ZHSCs) have an energy density of 102.9 Wh kg–1 and a power density of 395.8 W kg–1. This work develops a new strategy for the valuable application of BT in the production of high-yield carbon electrodes.