Vertical graphene nanosheetsmodiBed Al current collectors for high-performance sodium-ion batteries

Rechargeable sodium-ion batteries(SIBs)are promising candidates for large-scale energy storage owing to their excellent high-power performance.However,Al-based current collectorsat both anodes and cathodes of SIBs,which widely influence the power properties of a variety of electrodes in SIBs,have rarely been investigated.Here,we demonstrate that vertical graphene nanosheets grown on commercial Al foil by the plasma-enhanced chemical vapor deposition(PECVD)method,form a robust connection with the carbon-based conductive network of the electrode,thereby significantly reducing the electrode current collector interfacial resistance.For sodium vanadium phosphate(NVP)anodes with vertical graphenenanosheetmodified Al foil(G-AI)current collectors,the interfacial resistance between the electrode and current collector is reduced 20-fold compared with that in the case of Al foil.The G-AI current collector reduces the polarization and improves the rate capability compared with that of Al current collectors within both cathodes and anodes of SIBs.At a high rate of 5 C,the capacity retention of NVP cathode with G-AI current collector is 74%,which is much higher than that with AI foil(22%).We believe that the obtained results support the prospect for the widespread use of G-AI current collectors in the further improvement of high-power profiles of SIBs.