Optimizing Electrochemical Performance in Sodium-Ion Batteries using O3-type Na 0.90 Cu 0.22 Fe 0.30 Mn 0.48 O 2 and Hard Carbon

Abstract

Sodium-ion batteries (SIBs) are being viewed as a prime alternative to lithium-ion batteries (LIBs) due to their resource availability, cost-effectiveness, safety, and superior power performance. Layered transition metal oxide cathode materials, in particular, have garnered interest for their high theoretical capacity and extended cycle life. This study focuses on the O3-type Na 0.90 Cu 0.22 Fe 0.30 Mn 0.48 O 2 (NCFMO), synthesized using the polyvinylpyrrolidone combustion method, showcasing notable specific capacity and capacity retention of over 80% after 200 cycles at 1C. Hard carbon has been identified as a potential candidate for commercialization among various anode materials, due to its high reversible capacity and stable structure. We assembled and evaluated a coin SIB full cell comprised of an NCFMO cathode and hard carbon anode (HC), which demonstrated optimal electrochemical performance at a positive-to-negative capacity ratio of 0.9. The study also explored the influence of the electrolyte on electrochemical performance, with NaClO 4 (0.1 M NaClO 4 in PC = 100 Vol% with 2.0%FEC) found to deliver the best results. Further, we assessed the heat generation characteristics of the NCFMO/HC full cell, revealing higher total heat generation during charging compared to discharging. This comprehensive study contributes significantly to the ongoing efforts towards commercialization of SIBs.