Toluene‐Mediated Morphology Tuning of Diblock Copolymer‐Templated Porous Si/Ge/K/C Thin Films for Li‐Ion Batteries

Abstract

Amphiphilic diblock copolymer poly(styrene‐b‐ethylene oxide) templating in combination with sol–gel chemistry is utilized to synthesize porous mixed silicon/germanium/potassium/carbon (Si/Ge/K/C) thin films. As a Si/Ge source, the dissolvable Zintl phase K12Si12Ge5 is used. The toluene‐mediated morphological changes in the porous mixed Si/Ge/K/C thin films are studied with scanning electron microscopy and grazing incidence small/wide‐angle X‐Ray scattering. A dichloromethane solvent vapor annealing step is applied to study the additional morphological transformation inside the films. Since Ge and Si are promising anode materials in Li‐ion batteries, CR2032 half‐cells are manufactured with the porous mixed Si/Ge/K/C thin films and characterized by cyclic voltammograms, cycling, and impedance spectroscopy.

Keywords

• diblock copolymers
• Li-ion batteries
• porous films
• Si/Ge/K/C
• solvent vapor annealing