PDF Publication Title:
Text from PDF Page: 011
Batteries 2022, 8, 183 11 of 13 Before assembling the full cell, both electrodes were cycled separately in Na-metal cells for five cycles to compensate for the initial Na-consuming irreversible processes. The corresponding voltage profiles are shown in Figure 8a. The measured specific capacity of NVPF (in Figure 8b) corresponded to the expected one in the charging process, while it was a little bit lower upon discharge, which limited the coulombic efficiency to 80%. The voltage profiles (Figure 8c) of the full cell showed initial satisfying values of specific capacity, delivering almost 120 mAhg−1 during charging. Upon cycling, a de- livered capacity drop was evident, which was most likely associated with the relatively poor coulombic efficiency, thus leading to the Na-inventory depletion. The cell capacity decreased by about 47 mAhg−1 at cycle 50, which was associated with an increase in the coulombic efficiency, which reached 95%, as seen in Figure 8d. The assembling of a full-cell prototype represents a significant proof of concept for the eligibility of Na-ion batteries as a sustainable alternative to Li-ion ones, exploiting cheap and waste-recovered materials, especially in view of a possible scale-up of the production process. 4. Conclusions The disposal of face masks represents a relevant environmental issue after the outbreak of the coronavirus pandemic in late 2019. In this work, we studied the pyrolytic conversion of surgical and FFP2 FMs into hard carbons (biochar) to be used as anode materials in post-lithium batteries, specifically Na-ion batteries. The recovery of a waste stream being our main purpose rather than the development of new materials for energy applications, we adopted mild conditions for the carbonization process; no chemical pretreatment of the FMs was used and pyrolysis was carried out at 800 ◦C in a N2 atmosphere at ambient pressure for a relatively short time of 30 min. Both C-surgical and C-FFP2 combustion resulted in highly disordered carbons, the former characterized by bigger particles (up to 100 μm with respect to the submicrometric particles of C-FFP2). Additionally, both C-surgical and C-FFP2 were effectively tested in laboratory-scale Na-metal cells (with NaClO4 in PC as the electrolyte), displaying an acceptable specific ca- pacity along with a wide range of current regimes from C/20 to 1C (i.e., from 0.025 mA/cm2 to 0.5 mA/cm2). Here as well, considering the purpose of the work, no post-synthesis material activation was carried out and no specific selection of electrolyte and/or other additives to stabilize the cell behavior was decided. Of course, further optimization of the preparation strategy and the final cell configuration are expected to lead to enhanced performance. Furthermore, as a proof of concept of real battery operation, C-surgical was employed within a full Na-ion cell in combination with an NVPF cathode, always using NaClO4 in PC as electrolyte. The results evidenced the possibility of obtaining amorphous carbon from face mask disposal in relatively mild conditions (no pretreatment, low pyrolysis temperature and short time). The electrochemical performance obtained in such conditions, still to be optimized in terms of specific capacity output to comply with the current commercial application standards, represents a preliminary confirmation of the effective repurposing of disposed face masks into higher-value materials for large-scale energy storage from renewables by Na-ion batteries. Overall, the information provided here can inspire future activities aiming to find a sustainable utilization of disposed materials, opening up new directions to innovate both the electrodes and even the full-cell technology by repurposing and revalorizing waste materials. Author Contributions: Conceptualization, C.G.; FM pyrolysis and material characterization, M.B.; electrochemical tests and data analysis, S.P., A.P., N.P. and G.A.E.; NVPF preparation and testing, N.P., R.R.; writing, S.P., A.P. and M.B.; supervision, G.A.E., R.R., A.T. and C.G.; funding acquisition, C.G., A.T. and R.R. All authors have read and agreed to the published version of the manuscript. Funding: Ministry of Education, Universities and Research: PRIN N◦ 2017MCEEY4 funding.PDF Image | From Wastes to Anode Materials for Na-Ion Batteries
PDF Search Title:
From Wastes to Anode Materials for Na-Ion BatteriesOriginal File Name Searched:
batteries-08-00183.pdfDIY PDF Search: Google It | Yahoo | Bing
Salgenx Redox Flow Battery Technology: Salt water flow battery technology with low cost and great energy density that can be used for power storage and thermal storage. Let us de-risk your production using our license. Our aqueous flow battery is less cost than Tesla Megapack and available faster. Redox flow battery. No membrane needed like with Vanadium, or Bromine. Salgenx flow battery
CONTACT TEL: 608-238-6001 Email: greg@salgenx.com (Standard Web Page)