Design of hierarchical porous carbonaceous foams from a dual-template approach and their use as electrochemical capacitor and Li ion battery negative electrodes

Abstract

Porous carbon foams were prepared by pyrolysis of phenolic resin from a dual-template approach using silica monoliths as hard templates and triblock copolymers as soft templating agents. Macroporosity of 50-80% arose from the Si(HIPE) hard template (the acronym "HIPE" refers to the high internal phase emulsion process), while the soft template generated micro- or mesoporosity, according to the operating procedure. The final materials exhibited a Brunauer-Emmett-Teller specific surface area of 600-900 m 2·g -1. Their performances as electrodes for electrochemical capacitors or Li ion battery negative electrodes were investigated. The mesoporous foams gave the best capacitance, up to 20 F·g -1. In battery configuration, the microporous foams delivered an irreversible capacity of 500-600 mA·h·g -1 during the first discharge. Upon charging, partial extraction of Li gave reversible capacities of 125-150 mA·h·g -1. © 2011 American Chemical Society.