Binder-free electrophoretic deposition of Sb/rGO on Cu foil for superior electrochemical performance in Li-ion and Na-ion batteries
By Dashairya, Love; Das, Debasish; Saha, Partha
Published in Electrochimica Acta
Electrochimica Acta
2020
Abstract
Antimony (Sb) is a well-studied anode for lithium-ion/sodium-ion batteries (LIBs/SIBs) owing to its exceptionally high theoretical capacity ( 660 mAhg?1). However, abrupt capacity decay due to severe volumetric swelling ( 300%) associated with a fully lithiated/sodiated phase(s) impede the commercial applications. Even though various synthesis strategies able to control the volumetric swelling of Sb but the delamination of active mass from the Cu foil cannot be avoided. Keeping in mind that traditional doctor-blade slurry coating cannot prevent Sb delamination, herein, we show that electrophoretic deposition (EPD) of antimony nanoparticles (SbNPs) embedded in reduced graphene oxide (rGO) sheets on Cu foil is a viable technique to fabricate binder-free electrodes in quick time ( 3 min) preventing Sb delamination. In particular, nanostructured SbNPs/rGO derived from a hydrothermal method is successfully deposited on Cu foil using nickel nitrates/poly(acrylic acid) as dispersant and carbon black as a conductive agent in propanol. The SbNPs/rGO electrodes exhibit an exceptionally stable capacity of 370 mAhg?1 at 1C, and 350 mAhg?1 at 0.2C current rate for LIBs and SIBs, respectively, up to 100 cycles. Importantly, the rate capability of the electrodes also found excellent with capacity remains 170 mAhg?1 and Coulombic efficiency 99% at 6C current rate for LIBs. The SIBs also show similar performance and able to maintain capacity 235 mAhg?1 and Coulombic efficiency 99% at 4C current rate. Ex-situ phase and microstructural analysis reveal that cycled electrodes form a graphene nanoribbons interspersed with Sb nanoparticles and Li3Sb/Na3Sb phase during charge-discharge. It is proposed that hybrid nanostructure and synergy between uniquely placed graphene sheets and SbNPs generated by electrophoretic deposition prevents the active phase delamination and catastrophic failure ushering a time-saving strategy to fabricate binder-free electrodes for LIBs/SIBs.