Synthesis and Characterizations of Na4MnCr(PO4)3/rGO as NASICON-Type Cathode Materials for Sodium-ion Batteries

Abstract

NASICON-type Na4MnCr(PO4)3 (NMCP) wrapped with reduced graphene oxide (rGO) was synthesized via a simple sol-gel method as composite cathode material Na4MnCr(PO4)3/rGO (NMCP/rGO) for Na ion batteries. The surface morphology, crystal structure and pore size distribution of pristine NMCP and as-synthesized NMCP/rGO composite cathode are identified by X-ray diffraction (XRD), field emission-scanning electron microscopy (SEM), transmission electron microscope (TEM), the Brunauer–Emmett–Teller (BET) method and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of composition-optimized NMCP/rGO composite cathode presents stable capacity retention and rate capability. The capacity retention of as-synthesized NMCP/rGO composite is 63.8%, and average coulombic efficiency maintains over 98.7% for 200 cycles. The reversible capacity of as-synthesized NMCP/rGO composite cathode still retained 45 mAh/g and 38 mAh/g under a current density of 0.5 A/g and 1.0 A/g, respectively, which was better than that of pristine NMCP, with only 6 mAh/g and 4 mAh/g. The redox reactions of pristine NMCP and as-synthesized NMCP/rGO composite are studied via cyclic voltammetry. The improved electronic conductivity and structure stability of bare NMCP is attributed to the contribution of the rGO coating.

Synthesis and Characterization of MnIn2S4/Single-Walled Carbon Nanotube Composites as an Anode Material for Lithium-Ion Batteries

“…The surface area was drastically reduced after compositing with SWCNTs, but the average pore size rose noticeably. This could be attributed to the fact that SWCNTs cover the smaller micropores on MIS, resulting in a reduced contact area with nitrogen [ 23 , 35 ].…”

“…Both samples exhibited type-IV curves with hysteresis loops, indicating that the material had a mesopo- was drastically reduced after compositing with SWCNTs, but the average pore size noticeably. This could be attributed to the fact that SWCNTs cover the smaller microp on MIS, resulting in a reduced contact area with nitrogen [23,35]. XPS was used to analyze the MIS/SWCNT composites' elemental make-up and ch ical bonding states.…”

Insights and Nanoarchitectonics in Fe-Substituted Newer NaSICON Na4MnxFeyCrz(PO4)3Cathodes for Sodium-Ion Batteries

“…The recorded cyclic voltammogram in Figure a is a comparison plot of the three cathode materials, NMFCP 1028, NMFCP 8210, and NMFCP 5510, which portray three distinct redox pairs. The redox pairs at 3.5 and 4.2 V correspond, respectively, to the Mn 2+ to Mn 3+ and Mn 3+ to Mn 4+ conversion, while the redox pair at 2.7 V is due to Fe 2+ to Fe 3+ conversion. ,,− ,,,, Figure b shows a comparison of galvanostatic charge–discharge profiles of the fifth cycle of the three cathode materials at 0.1C rate ( C = 110.67 mAh g –1 , considering two electron transfers). NMFCP 1028 delivered a specific capacity of 74 mAh g –1 , which was the highest among the three cathode materials, followed by NMFCP 8210 with 67 mAh g –1 and NMFCP 5510 with 65 mAh g –1 .…”

“…A viable approach to elevate the potential is to replace metal atoms with stable multivalent transition-metal atoms within NaSICON structures. Although the electrochemical properties of newer NaSICONs, such as Na 4 MnV­(PO 4 ) 3 , Na 4 MnTi­(PO 4 ) 3 , Na 3 MnZr­(PO 4 ) 3 , Na 4 Mn 0.5 Fe 0.5 Al­(PO 4 ) 3 , and Na 4 MnCr­(PO 4 ) 3 , have been analyzed, − researchers have recently shown increased interest in Mn- and Cr-based NaSICONs due to their high working potential around 4.4 V vs Na/Na + . − However, the literature on these NaSICONs is scarce, with only a few studies published in the past 3 years. This scarcity of research presents a significant opportunity to explore this material for sodium-ion storage.…”