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 m2·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.