Self-Organizing Batteries

Abstract

Abstract : This research aimed to use colloidal self-organization to create complete bipolar electrochemical devices. In this approach, repulsive and attractive surface forces are introduced within device structures to form: nanoscale electrochemical junctions between electronically conductive anodes and cathodes; electronically conductive networks of storage materials particles; and electrical connections to the external circuit via selective attachment of particles to current collectors. Rechargeable lithium batteries were used as a testbed device for this approach. In particular, efforts were aimed at enabling a self-organized architecture in which a continuously percolating cathode network is wired to one current collector and an anode network to the other, while the two networks are isolated everywhere from one another by repulsive surface forces. Repulsive dispersion forces (negative Hamaker constant) and other surface forces were used to create permanent electrochemical junctions that upon drying or solidification of the liquid medium are fitted by solid polymer electrolyte, resulting in solid-state devices. Such batteries could be economically fabricated at sizes and shapes ranging from printed microbatteries to large-scale continuous coatings, and would have increased energy and power densities due to improved packing and reduced transport distances. This work represents a fundamentally new approach to electrochemical device fabrication, ultimately applicable to a broad range of DoD technologies.