Fernández-Ropero Antonio J, Zarrabeitia Maider, Baraldi Giorgio, Echeverria Maria, Rojo Teofilo, Armand Michel, Shanmukaraj Devaraj
Centre for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain.
Inorganic Chemistry Department, University of the Basque Country UPV/EHU, P.O. Box. 644, 48080 Bilbao, Spain.
ACS Appl Mater Interfaces. 2021 Mar 17;13(10):11814-11821. doi: 10.1021/acsami.0c20542. Epub 2021 Mar 2.
The abundance of the available sodium sources has led to rapid progress in sodium-ion batteries (SIBs), making them potential candidates for immediate replacement of lithium-ion batteries (LIBs). However, commercialization of SIBs has been hampered by their fading efficiency due to the sodium consumed in the formation of solid-electrolyte interphase (SEI) when using hard carbon (HC) anodes. Herein, NaCO sodium salt is introduced as a highly efficient, cost-effective, and safe cathode sodiation additive. This sustainable sodium salt has an oxidation potential of ∼4.0 V vs Na/Na°, so it could be practically implemented into SIBs. Moreover, for the first time, we have also revealed by X-ray photoelectron spectroscopy (XPS) that in addition to the compensating Na ions spent in the SEI layer, the high specific capacity and capacity retention observed from electrochemical measurements are due to the formation of a thinner and more stable cathode-electrolyte interphase (CEI) on the P2-NaMnFeTiO while using such a cathode sodiation additive. Half-cell studies with P2-NaMnFeTiO cathodes show a 27% increase in the specific capacity (164 mAh g) with cathode sodiation additives. Full-cell studies with the HC anode show a 4 times increase in the specific capacity of P2-NaMnFeTiO. This work provides notable insights into and avenues toward the development of SIBs.
丰富的可用钠源推动了钠离子电池（SIB）的快速发展，使其成为立即取代锂离子电池（LIB）的潜在候选者。然而，由于使用硬碳（HC）阳极时在固体电解质界面（SEI）形成过程中消耗钠，导致SIB的效率下降，阻碍了其商业化。在此，引入NaCO钠盐作为一种高效、经济且安全的阴极钠化添加剂。这种可持续的钠盐相对于Na/Na°的氧化电位约为4.0 V，因此可以实际应用于SIB。此外，我们首次通过X射线光电子能谱（XPS）揭示，除了在SEI层中消耗的补偿性Na离子外，电化学测量中观察到的高比容量和容量保持率归因于在使用这种阴极钠化添加剂时，在P2-NaMnFeTiO上形成了更薄且更稳定的阴极-电解质界面（CEI）。使用P2-NaMnFeTiO阴极的半电池研究表明，添加阴极钠化添加剂后比容量增加了27%（164 mAh g）。使用HC阳极的全电池研究表明，P2-NaMnFeTiO的比容量增加了4倍。这项工作为SIB的发展提供了显著的见解和途径。
