Particle/polymer electrospinning was used to prepare fiber mat cathodes containing LiCoO2 nanoparticles, carbon powder, and poly(vinylidene fluoride) for Li-ion batteries. The fibers had a high LiCoO2 particle content (70wt%) which allowed for a high gravimetric capacity of 90mAhg−1 (corresponding to 128 m A h g L i C o O 2 − 1 ) at 0.1C (1C=274 m A h g L i C o O 2 − 1 ). Cathode performance was stable in a half cell with 78% capacity retention over 200 cycles at 0.5C. Unlike previous work on electrospun LiCoO2 nanofibers prepared using sol-gel chemistry and high temperature processing, the particle/polymer fiber mat cathodes reported here were made thick with a high fiber volume fraction for high areal and volumetric capacities at fast charge/discharge rates (e.g., 0.81mAhcm−2 and 62mAhcm−3 at 2C) which were much greater than that of a slurry cast cathode of the same composition (0.004mAhcm−2 and 0.30mAhcm−3 at 2C). Full cells containing a LiCoO2/C/PVDF fiber mat cathode and C/PVDF fiber mat anode were also prepared and characterized. These electrospun batteries exhibited a high energy density of 144Whkg−1 at 0.1C and an areal capacity of 1.03mAhcm−2 at 1C. The excellent performance of the electrospun particle/polymer cathodes and anodes is attributed to electrolyte penetration throughout the 3D fiber electrode mats, a large electrode/electrolyte interfacial area, and short Li+ transport pathways between the electrolyte and active material nanoparticles in the radial fiber direction.