Aqueous Processing of Na_0.44MnO₂ Cathode Material for the Development of Greener Na-Ion Batteries

Abstract

The implementation of aqueous electrode processing of cathode materials is a key for the development of greener Na-ion batteries. Herein, the development and optimization of the aqueous electrode processing for the ecofriendly NaMnO (NMO) cathode material, employing carboxymethyl cellulose (CMC) as binder, are reported for the first time. The characterization of such an electrode reveals that the performances are strongly affected by the employed electrolyte solution, especially, the sodium salt and the use of electrolyte's additives. In particular, the best results are obtained using the 1 M solution of NaPF in EC/DEC (ethylene carbonate/diethyl carbonate) 3:7 (v/v) + 2 wt % FEC (fluoroethylene carbonate). With this electrolyte, the outstanding capacity of 99.7 mA h g is delivered by the CMC-NMO cathode after 800 cycles at a 1C charge/discharge rate. On the basis of this excellent long-term performance, a full sodium cell, composed of a CMC-based NMO cathode and hard carbon from biowaste (corn cob), has been assembled and tested. The cell delivers excellent performances in terms of specific capacity, capacity retention, and long-term cycling stability. After 75 cycles at a C/5 rate, the capacity of the NMO in the full-cell approaches 109 mA h g with a Coulombic efficiency of 99.9%.

High-Performance Na0.44MnO2 Slabs for Sodium-Ion Batteries Obtained through Urea-Based Solution Combustion Synthesis

“…(Figure 3a,b) is mainly composed of sub-micrometric slabs of 100-400 nm width and 0.6-1.4 µm length. Hence, the particle morphology of SC-NMO is similar to that of Na 0.44 MnO 2 reported in our previous work [29]. However, the dimensions of the SC-NMO slabs are smaller and surfaces of the slabs are less defined as compared to SS-NMO (Figure 3c).…”

“…Figure 5 reports the cycling performance of the SC-NMO at increasing C rates (C/10, C/5, C/2, 1 C, 2 C and 5 C) and during the long-term cycling test at 1 C. In addition, selected potential profiles of SC-NMO, recorded at different C-rates and during the 1st and 2nd cycle at C/10 are also given. The galvanostatic cycling data are compared with SS-NMO to reveal the impact of the modified synthesis conditions [29]. The capacities at C/10 are approximately 115 mA h g −1 , i.e., in very good agreement with literature data and close to the theoretical capacity of 121 mA h g −1 .…”

“…Interestingly, the SC-NMO capacity is completely retained (around 108 mA h g −1 ) when current is changed to C/10 after the long-term cycling at 1 C. This suggests that the fading performance during long-term cycling is correlated with the composite electrode degradation rather than the irreversible structural degradation of the active material. [29] and the SC-NMO-based electrode presented in this work: the tested C rates are: C/10, C/5, C/2, 1 C, 2 C, 5 C; (b,c) show the potential profiles of SC-NMO, respectively, during the 3rd discharge and charge cycle at each C rate; (d) "Potential vs. x Na in Na x MnO 2 " graph reported for the 1st and 2nd cycles at C/10. The arrows show if the material is increasing or decreasing its sodium content while cycling; (e) 1 C long-term cycling comparison between SC-NMO-based electrode (200 cycles) and SS-NMO-based electrode (150 cycles-reported in our previous work [29]); (f) selected potential profiles of SC-NMO upon cycling (panel e).…”

A Water‐Soluble NaCMC/NaPAA Binder for Exceptional Improvement of Sodium‐Ion Batteries with an SnO2‐Ordered Mesoporous Carbon Anode

“…[40] It was recently reported that aN a 3 V 2 (PO 4 ) 2 F 3 cathode with NaCMC binder has excellent high-rate performance and cycle life (i.e., 75 mAh g À1 @70 Ca nd 79 %c apacity retention after 3500 cycles). [25,41,42] However,o pposite results have also been reported;f or example, as odium Prussian blue/PVDF electrode showed superiorc harge-discharge performance to that prepared with NaCMCb inder. [25,41,42] However,o pposite results have also been reported;f or example, as odium Prussian blue/PVDF electrode showed superiorc harge-discharge performance to that prepared with NaCMCb inder.…”

“…[22][23][24][25][26] Cost-effectiveness and large-scale applications are emphasized for NIBs. [22][23][24][25][26] Cost-effectiveness and large-scale applications are emphasized for NIBs.…”