Using polymer templated nanoporous materials to improve performance in electrochemical pseudocapacitors and batteries

Block-copolymer templating of inorg. frameworks provides a powerful route to produce periodic nanoporous materials with well-defined nanoscale architectures, controlled porosity, and high surface area. Such control is important for batteries and pseudocapacitors, where performance is detd. by elec. connectivity, electrolyte access, and surface redox. Here, we specifically examine porous pseudocapacitors built from nanocrystal building-blocks. The architecture produces fast redox kinetic from a broad range of porous metal-oxides materials. Composite systems can also be produced that combine efficient elec. cond. with kinetically accessible redox sites. Finally, in some materials we find that pore flexibility combined with short diffusion lengths produces a phenomena called intercalation pseudocapacitance, where traditional battery-like intercalation become kinetically facile. For high-capacity anodes, we examine porous silicon produce by redn. of template porous silica. Here, the mech. flexibility of nanoporous materials can produce robust cycling behavior, despite the large vol. increase that occurs in silicon upon alloying with lithium.