Abstract
In carbon engineering, a longstanding trade-off persists: chemical activation increases surface area but sacrifices conductivity, whereas graphitization enhances conductivity at the expense of porosity. In 2017, we introduced an electrochemical graphitization strategy using cathodic polarization in CaCl2-NaCl molten salts to convert hard carbon into graphite. Here, we reveal that this graphitization process initiates at the surface and propagates inward, enabling the transformation of mesoporous hard carbon into surface-graphitized mesoporous carbon. Meanwhile, this phenomenon is an electrochemical activation process: short-term graphitization rearranges carbon atoms to increase surface area from 397 to 867 m2/g, without significant mass loss. Unlike chemical activation, which achieves similar surface area gains at the cost of >50% yield loss, our method maintains nearly 100% carbon yield while preserving mesoporosity. The resulting material delivers a 17-fold increase in electrical conductivity (26–450 S/cm). This scalable, energy-efficient approach resolves the long-standing graphitization–porosity dilemma, producing carbons with both high conductivity and large accessible surface area.
| Original language | English |
|---|---|
| Journal | Advanced Science |
| DOIs | |
| State | Accepted/In press - 2026 |
Funding
The electrochemical graphitization (Y.Y., B.P., H.L., and S.D.) is supported by the Critical Materials Innovation Hub, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Critical Minerals and Energy Innovation (CMEI), Advanced Materials and Manufacturing Technologies Office (AMMTO). The energy storage study (J.F., T.W.) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. The Raman investigation (N.S.) was supported by a US DOE Office of Science Distinguished Scientist Fellows award at ORNL. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non‐exclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The DOE will provide public access to these results of federally sponsored research under the DOE Public Access Plan (http://energy.gov/downloads/doe‐public‐access‐plan). This research uses resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to GP‐SANS (CG2). Part of this work was conducted at the NOMAD beamlines at ORNL's Spallation Neutron Source, which was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, U.S. Department of Energy.
Keywords
- electrical conductivity
- electrochemical activation
- mesoporous carbon
- molten salts
- porosity engineering