Camphene-Assisted Fabrication of Free-Standing Lithium-Ion Battery Electrode Composites

Abstract

Free-standing electrode (FSE) architectures hold the potential to dramatically increase the gravimetric and volumetric energy density of LIBs by eliminating the parasitic dead weight and volume associated with traditional metal foil current collectors, however current FSE fabrication methods suffer from insufficient mechanical stability, electrochemical performance, or industrial adoptability. Here, we demonstrate a scalable camphene-assisted fabrication method that allows simultaneous casting and templating of FSEs comprised of common LIB materials with performance superior to foil-cast counterparts. These porous, lightweight, and robust electrodes simultaneously enable enhanced rate performance by improving mass and ion transport within the percolating conductive carbon pore network and eliminating current collectors for efficient and stable Li+ storage (> 1000 cycle in half-cells) at increased gravimetric and areal energy densities. Compared to conventional foil-cast counterparts, the camphene-derived electrodes exhibit ~1.5x enhanced gravimetric energy density, increased rate capability, and improved capacity retention in coin-cell configurations. A full cell with free-standing anode and cathode cycled for over 250 cycles with greater than 80% capacity retention at an areal capacity of 0.73 mAh/cm2. This active-material-agnostic electrode fabrication method holds potential to tailor the morphology of flexible, current-collector-free electrodes to optimize LIBs for high power or high energy density Li+ storage and is applicable to other electrochemical technologies and advanced manufacturing methods.