Jute-Based Porous Hard Carbon Anode for Cheaper, Sustainable Non-Aqueous Sodium-Ion Batteries

Sodium-ion batteries (SIBs) demonstrate significant potential to replace existing lithium-ion batteries (LIBs) technology due to the abundant sodium and similar ion-storage chemistry as LIBs.¹ Among anode materials, hard carbon (HC) is very popular due to its high capacity and excellent structural stability.² The price ($/kg) of commercial HC will be inexpensive if the commercial production moves into sustainable and fiscal HC precursors such as pet coke and biomass.³<br/>In this study, cost-effective jute fiber-based hard carbon (JHC) synthesized through direct pyrolysis at 800°C under the inert atmosphere has been explored as an anode material for SIBs. The yield (%) of HC per kg of jute is ~34%, which reduces manufacturing cost ($/kg) for JHC to 4 times cheaper than sugar precursors and 1.5 times more affordable than other biomass-derived HC, respectively. JHC delivered the high reversible capacity of 328 mAhg^-1 comparable with the reported reversible capacity at 30 mAg^-1 current density.⁴ It exhibits excellent capacity retention of 83.5% after 100 long cycles using non-aqueous electrolytes as 1M NaPF₆ in a binary solvent of ethylene carbonate (EC) and diethyl carbonate (DEC). Moreover, the KOH activated highly porous JHC shows the reversible capacity of 280 mAhg^-1 with 81% capacity retention after 100 cycles. JHC without activation having low-surface-area improves the first cycle Coulombic efficiency (FCE) from 45% to 66% with excellent retention and rate performance till 2C. The plateau-based capacity (below 0.1V) contribution in JHC is around 43% of total capacity responsible for high rate, high cyclable carbon anode, whereas activated JHC shows more capacitive like behavior. Thus, jute fiber precursor could be the best choice for the cost-effective hard carbon anode for sodium-ion battery technology.<br/><br/><b>References:</b><br/>(1) Dou, X.; Hasa, I.; Saurel, D.; Vaalma, C.; Wu, L.; Buchholz, D.; Bresser, D.; Komaba, S.; Passerini, S. Hard Carbons for Sodium-Ion Batteries: Structure, Analysis, Sustainability, and Electrochemistry. <i>Materials Today</i>. <b>2019</b>, pp 87–104. https://doi.org/10.1016/j.mattod.2018.12.040.<br/>(2) Nagmani.; Puravankara, S. Insights into the Plateau Capacity Dependence on the Rate Performance and Cycling Stability of a Superior Hard Carbon Microsphere Anode for Sodium-Ion Batteries. <i>ACS Appl. Energy Mater.</i> <b>2020</b>, <i>3</i> (10), 10045–10052. https://doi.org/10.1021/acsaem.0c01750.<br/>(3) Peters, J. F.; Cruz, A. P.; Weil, M. Exploring the Economic Potential of Sodium-Ion Batteries. <i>Batteries</i> <b>2019</b>, <i>5</i> (1), 10. https://doi.org/10.3390/batteries5010010.<br/>(4) Yu, P.; Tang, W.; Wu, F. F.; Zhang, C.; Luo, H. Y.; Liu, H.; Wang, Z. G. Recent Progress in Plant-Derived Hard Carbon Anode Materials for Sodium-Ion Batteries: A Review. <i>Rare Met.</i> <b>2020</b>, <i>39</i> (9), 1019–1033. https://doi.org/10.1007/s12598-020-01443-z.