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. [ABSTRACT FROM AUTHOR]