Operando mechanistic and dynamic studies of N/P co-doped hard carbon nanofibers for efficient sodium storage

In situ Raman and electrochemical results reveal that Na⁺ adsorbs on the surface/defective sites of N/P-HCNF and inserts randomly into its turbostratic nanodomains in the dilute state without a staged formation, which can facilitate fast Na⁺ diffusion kinetics for efficient sodium storage.