Design of Hierarchical Porous Carbonaceous Foams from a Dual-Template Approach and Their Use as Electrochemical Capacitor and Li Ion Battery Negative Electrodes

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).