ABSTRACT
NaClO4 and NaPF6, the most universally adopted electrolyte salts in commercial sodium-ion batteries (SIBs), have a decisive influence on the interfacial chemistry, which is closely related to electrochemical performance. The complicated and ambiguous interior mechanism of microscopic interfacial chemistry has prevented reaching a consensus regarding the most suitable sodium salt for high-performance SIB electrolytes. Herein, we reveal that the solvation structure induced by different sodium salt anions determines the Na+ desolvation kinetics and interfacial film evolution process. Specifically, the weak interaction between Na+ and PF6- promoted sodium desolvation and storage kinetics. The solvation structure involving PF6- induced the anion's preferential decomposition, generating a thin, inorganic compound-rich cathode-electrolyte interphase that ensured interface stability and inhibited solvent decomposition, thereby guaranteeing electrode stability and promoting the charge transfer kinetics. This study provides clear evidence that NaPF6 is not only more compatible with industrial processes but also more conducive to battery performance. Commercial electrolyte design employing NaPF6 will undoubtedly promote the industrialization of SIBs.
ABSTRACT
The cellulose nanocrystals (CNC) has attracted widespread attention in reinforced materials. However, the application of CNC in electrospinning has been limited due to its self-polymerization. Herein, a cobweb-like nanofibrous membrane was fabricated by electrospinning the polyacrylonitrile (PAN) and sulfydryl-functionalized CNC (SC). The SC content could reach to 48 wt% after the thiolation modification. The membrane with ultrafine fibers and interlaced nets possessed outstanding porosity (91.7%) and underwater superoleophobicity. An ultrahigh permeation flux of 1244 L·m-2·h-1 with a separation efficiency of >99.9% was achieved driven by gravity. The mechanical properties also enhanced significantly with the increase of SC. When the addition amount of SC was 48 wt%, the maximum tensile stress was 2.9 MPa, which was 3.4 times than that of the PAN membrane. The antifouling performance and chemical stability endowed the SC(48)/PAN membrane with intriguing reusability, thus making it exhibit enormous potential in oil/water separation.
