Hollow Carbon Fiber Electrode Flow Cell Batteries

Renewable and low/zero carbon emission energy sources are an important part of a low pollution, stable climate future. Many renewable energy sources are plagued by being intermittent, and thus infrastructure-scale storage is needed for these to be viable. Secondary rechargeable batteries for storage of energy are needed to address the spatial and temporal mismatch between supply and demand. A promising means of storing electrical energy are flow-cell batteries; these allow the storage of active materials to be decoupled from the energy conversion process, improving safety, lifespan through blocking self-discharge, and allowing scaling of energy storage and production independently. While a progress has been made in developing efficient chemistries and components of these devices, they suffer from a low energy density when compared to incumbent technology (viz. lithium-based batteries); supporting structures and other inactive components occupy most of the volume of a typical flat plate flow cell, so despite improvements in areal current density, most of the device is inactive and cannot contribute power. Some researchers have sought to overcome these limitations by adopting a tubular geometry, both on a macroscopic scale, and on a micro scale, which improves energy density and can eliminate the need for some components like bipolar plates, supports, and expensive membrane systems. The proposed research will build on recent work using bundled microtubular flow cells, which research suggests could yield orders of magnitude greater energy density than typical flat plate cells. In addition, it will leverage CAER technology for making hollow carbon fiber membranes, that will form the heart of the proposed cells.