High Performance Particle/Polymer Nanofiber Anodes for Li‐ion Batteries using Electrospinning

Electrospun nanofiber mats containing carbon nanoparticles in a poly(vinylidene fluoride) binder were prepared and characterized as Li‐ion battery anodes. The mats exhibited an initial capacity of 161 mAh g −1 with 91.7 % capacity retention after 510 cycles at 0.1  C (1  C =372 mA g carbon −1 ). Whereas many nanoscale electrodes are limited to low areal and/or volumetric capacities, the particle/polymer nanofiber anodes can be made thick with a high fiber volume fraction while maintaining good rate capabilities. Thus, a nanofiber anode with a fiber volume fraction of 0.79 exhibits a volumetric capacity of 55 mAh cm −3 at 2  C , which is twice that of a typical graphite anode. Similarly, thick nanofiber mats with a high areal capacity of 4.3 mAh cm −2 were prepared and characterized. The excellent performance of electrospun anodes is attributed to electrolyte intrusion throughout the interfiber void space and efficient Li + transport between the electrolyte and carbon nanoparticles in the radial fiber direction.