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

Continually increasing technological demands and widespread adoption of electric vehicles has spurred significant motivation to improve the performance of lithium-ion batteries (LIBs). In addition to improving intrinsic battery chemistry, optimizing electrode morphology and cell design can unlock increased energy density and rate capability to enable the adoption of next generation LIBs for societal decarbonization. Although 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, current FSE fabrication methods suffer from insufficient mechanical stability, electrochemical performance, or industrial adaptability. 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 freestanding 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 the 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