A hard carbon sheet-like structure has been successfully prepared with a short flow process by simply using cherry petals (CPs) as the raw materials. The sodium storage mechanism in CPs was detected with cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). Encouragingly, when being assessed as an anode electrode for sodium-ion batteries (SIBs), the CP electrode can provide a high initial reversible capacity of 310.2 mA h g⁻¹ with a favorable initial Coulomb efficiency of 67.3%, delivering a high retention rate of 99.3% at 20 mA g⁻¹ after 100 cycles. Even at a high current density of 500 mA g⁻¹, the reversible capacity can reach 146.5 mA h g⁻¹, indicating that the high rate performance is excellent as well. Such a preferable performance may be derived from the prepared structures with sufficient mesopores, the presence of nitrogen/oxygen functional groups on the surface and the expanded interlayer distances (∼0.44 nm), which enable reversible sodium-ion storage through surface adsorption and sodium intercalation.

NASICON-type (lithium super ionic conductor) solid electrolyte is of great interest because of its high ionic conductivity, wide potential window, and good chemical stability. In this paper, the key problems and challenges of NASICON-type solid electrolyte are described from the aspects of ionic conductivity, electrode interface, and electrochemical stability. Firstly, the migration mechanism of lithium ion is analyzed from the three-dimensional structure of NASICON-type solid electrolyte, and progress in the research of conductivity and stability is summarized. Then, the effective methods to reduce interface impedance and improve the cycle stability of all-solid-state lithium batteries (ASSLBs) with NASICON-type solid electrolyte are introduced. Finally, solutions to improve the conductivity of electrolytes and deal with electrode/electrolyte interface problems are summarized, and the development prospects of ASSLBs are discussed.