Novel fuel cell nanofibrous electrodes with a higher degree of Pt exploitation and higher durability compared to commercial standards are produced, based on self-standing electrospun CNF webs covered by Pt ultrathin nanoislands deposited by high overpotential pulsed electrodeposition.

Self-standing carbon nanofibers (CNF) were electrospun and tested in K-ion batteries (KIB). The comparison of the electrochemical performance of KIB using potassium bis(fluorosulfonyl)imide (KFSI) and potassium hexafluorophosphate (KPF 6) carbonate-based electrolytes revealed that, despite the coulombic efficiency is more readily stabilized with KFSI than with KPF 6 , the long-term cycling is quite the same, with a specific capacity of 200 mAh.g-1 for the CNF electrode. Post-mortem X-ray photoelectron spectroscopy analysis shows a more stable solid electrolyte interphase (SEI) for KIB employing KFSI. Finally, the K + ion storage mechanism was investigated by combining cyclic voltammetry and operando Raman spectroscopy, highlighting a combination of adsorption and intercalation processes. However the rate capability is better with the KPF 6 salt due to SEI layers formed at both CNF and K metal electrode, highlighting that full cell may lead to even superior results.