Title: A Generic Model for Electric Double Layers in Porous Electrodes

Abstract

The performance of electric-double-layer capacitors (EDLCs) hinges on microscopic charge distributions near the electrode/electrolyte interfaces. Whereas practical EDLCs consist of electrodes made of amorphous porous materials, theoretical understanding of EDLCs is mostly based on EDL structure near a planar surface or on simplistic models that have little relevance to realistic systems. In this work, we propose a spherical shell model to account for both pore size and curvature effects of amorphous porous materials. The EDL structure in spherical shells has been investigated over a broad range of pore sizes and curvatures by use of classic density functional theory. Theoretical results reveal that the curvature effects on convex and concave EDLs are drastically different and that materials with extensive convex surfaces will lead to maximized capacitance. Like a slit pore, the spherical shell model also predicts oscillatory variation of capacitance with pore size, but the oscillatory behavior is magnified as the curvature increases. The joint effects of pore size and curvature identified in this work give new insight into materials design for porous electrodes with optimal EDLC performance.

Authors:

Lian, Cheng ^[1]; Jiang, De-en ^[2]; Liu, Honglai ^[3]; Wu, Jianzhong ^[2]

---

+ Show Author Affiliations

1. East China Univ. of Science and Technology, Shanghai (China); Univ. of California, Riverside, CA (United States)
2. Univ. of California, Riverside, CA (United States)
3. East China Univ. of Science and Technology, Shanghai (China)

Publication Date:

Wed Apr 06 00:00:00 EDT 2016

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1388525

Grant/Contract Number:  

ERKCC61

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 120; Journal Issue: 16; Related Information: FIRST partners with Oak Ridge National Laboratory (lead); Argonne National Laboratory; Drexel University; Georgia State University; Northwestern University; Pennsylvania State University; Suffolk University; Vanderbilt University; University of Virginia; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); solar (fuels); energy storage (including batteries and capacitors); hydrogen and fuel cells; electrodes - solar; mechanical behavior; charge transport; materials and chemistry by design; synthesis (novel materials)