Fabricating Na/In/C Composite Anode with Natrophilic Na-In Alloy Enables Superior Na Ion Deposition in the EC/PC Electrolyte

摘要

In conventional ethylene carbonate(EC)/propylene carbonate(PC)electrolyte,sodium metal reacts spontaneously and deleteriously with solvent molecules.This significantly limits the practical feasibility of high-voltage sodium metal batteries based on Na metal chemistry.Herein,we present a sodium metal alloy strategy via introducing NaIn and Na_(2)In phases in a Na/In/C composite,aiming at boosting Na ion deposition stability in the common EC/PC electrolyte.Symmetric cells with Na/In/C electrodes achieve an impressive long-term cycling capability at 1 mA cm^(-2)(>870 h)and 5 mA cm^(-2)(>560 h),respectively,with a capacity of 1 mAh cm^(-2).In situ optical microscopy clearly unravels a stable Na ion dynamic deposition process on the Na/In/C composite electrode surface,attributing to a dendrite-free and smooth morphology.Furthermore,theoretical simulations reveal intrinsic mechanism for the reversible Na ion deposition behavior with the composite Na/In/C electrode.Upon pairing with a highvoltage NaVPOF cathode,Na/In/C anode illustrates a better suitability in SMB s.This work promises an alternative alloying strategy for enhancing Na metal interfacial stability in the common EC/PC electrolyte for their future applications.