Heavy Metal-Free Tannin from Bark for Sustainable Energy Storage

Rui Katahira, Peter Ciesielski, Michael Himmel, Alolika Mukhopadhyay, Yucong Jiao, Hongli Zhu

Research output: Contribution to journalArticlepeer-review

45 Scopus Citations


A novel renewable cathode made from earth abundant, low-cost materials can contribute to the intermittent storage needs of renewable energy-based society. In this work, we report for the first-time tannin from Nature as a cathode material. Our approach exploits the charge storage mechanism of the redox active quinone moiety. Tannins extracted from tree bark using environmental friendly aqueous solvents have the highest phenol content (5.56 mol g-1) among all the natural phenolic biopolymers, 5000 times higher than lignin. Tannins coupled with a conductive polymer polypyrrole acquire high specific capacitance values of 370 F g-1 at 0.5 A g-1 as well as excellent rate performance of 196 F g-1 at 25 A g-1. Additionally, we employed carbonized wood as an electrode substrate to produce a sustainable electrochemical device with dramatically improved performance compared to conventional devices. The high surface area provided by the well-aligned, cellular porosity of wood-derived substrate combined with the high mobility of ions and electrons in the carbonized cell walls and deposited tannin can achieve an areal capacitance of 4.6 F cm-2 at 1 mA cm-2, which is 1.5 times higher than activated wood carbon.

Original languageAmerican English
Pages (from-to)7897-7907
Number of pages11
JournalNano Letters
Issue number12
StatePublished - 13 Dec 2017

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.

NREL Publication Number

  • NREL/JA-2700-70637


  • bioinspired
  • biopolymer
  • carbonized wood
  • cathode
  • electroactive phenol
  • renewable
  • Tannins


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