# Integrated Performance Metrics of Porous Carbon Toward Practical Supercapacitor Devices

## TL;DR

This paper introduces a new tool and metric to predict and evaluate the energy density of supercapacitor devices using activated carbon materials.

## Contribution

A novel E-tool and descriptor η that integrate capacitance and porosity for predicting supercapacitor energy density.

## Key findings

- The required amount of electrolyte depends on both capacitance and porosity of activated carbon materials.
- The E-tool enables early prediction of device-level energy density from material properties.
- The descriptor η shows a linear relationship with the energy density of supercapacitor devices.

## Abstract

This work establishs a guidance of required amount of electrolyte for activated carbons in supercapacitor devices.A novel E-tool is provided for predicting the energy density of supercapacitor devices via the inputting of intrinsic parameters of activated carbons.A new descriptor η, that integrates capacitance and porosity of activated carbon electrode, is able to quickly evaluate the energy density of supercapacitor devices.

This work establishs a guidance of required amount of electrolyte for activated carbons in supercapacitor devices.

A novel E-tool is provided for predicting the energy density of supercapacitor devices via the inputting of intrinsic parameters of activated carbons.

A new descriptor η, that integrates capacitance and porosity of activated carbon electrode, is able to quickly evaluate the energy density of supercapacitor devices.

The online version contains supplementary material available at 10.1007/s40820-026-02069-z.

The scientific communities in both academia and industry are devoted to increasing energy density of supercapacitor devices, including investigating the relationship between carbon structure and capacitance of various activated carbon (AC) materials. However, most reported capacitance values are measured solely at the material level, which are difficult to directly translate into achievable energy densities for practical supercapacitor devices. In this work, we assemble supercapacitor pouch cells to reveal the insight relationships between the capacitance and porosity of AC materials and the optimal amount of electrolyte at the device level. Concurrently, a guidance on the required amount of electrolyte is provided, indicating that both the specific capacitance and porosity of AC materials collectively determine the energy density of a practical device (Edevice). Furthermore, we develop a computational E-tool for directly predicting Edevice at an early stage of material-level electrochemical testing. Finally, we propose a new descriptor (η) that incorporates both the capacitance and porosity parameters of AC materials, which displays a linear relationship with Edevice. This study provides a reliable E-tool and η for accelerating the development of advanced charge storage mechanisms and carbon materials for practical supercapacitor devices.

The online version contains supplementary material available at 10.1007/s40820-026-02069-z.