Structure, Composition, Transport Properties, and Electrochemical Performance of the Electrode‐Electrolyte Interphase in Non‐Aqueous Na‐Ion Batteries

Abstract

Great research efforts have been made towards the development of new battery materials that increase cycle life, safety, and energy density, as well as power density [4,5] along with investigations focused on understanding novel battery chemistries that can become an alternative to the dominant liquid electrolyte-based Li-ion battery technology. [6][7][8][9][10] Na-ion technologies have emerged as one of the most promising for battery applications. [11][12][13][14][15] Interestingly, while the attention is on a given battery chemistry that promises one order of magnitude increase of the energy density, [16,17] or in a specific electrode material that outperforms currently available electroactive materials in terms of specific capacity or operating voltage, [18][19][20] there is a tendency to overlook the crucial role that battery interfaces play in the safety, power capability, morphology of lithium deposits, shelf-life, and cycle life of the battery. [21] The success of commercial Li-ion rechargeable batteries was possible due to the correct selection of electrolyte materials that resulted in the formation of a stable anode-electrolyte interface, [22] known as the solid electrolyte interphase (SEI) as proposed by Peled. [23] This highlights how interfacial stability is crucial for battery development, becoming a bottleneck even when the ideal battery materials are chosen yet the battery interfaces prevent the optimum ionic or electronic transport, the correct adhesion among components, or the long term stability required for commercial battery operation.The nature of the SEI has led to the use of different modeling approaches [24][25][26][27][28][29][30] and surface-specific experimental techniques for its characterization. Among the most widely used analytical techniques, ex situ [31] and in situ [32] Fourier transform infrared (FTIR) spectroscopy, Raman microscopy, and spectroscopy [33,34] along with refinements such as shell-isolated nanoparticles for enhanced Raman spectroscopy (SHINERS), [35] electrochemical quartz crystal microbalance (EQCM), [36] spectroscopic ellipsometry, [37] atomic force microscopy (AFM), [38] X-ray photoelectron spectroscopy (XPS) [39][40][41] including the use of the Auger parameter [42] or other charge correction methods [43] for peak assignment, nuclear magnetic resonance (NMR), [44] X-ray absorption spectroscopy (XAS), [45] soft X-ray absorption spectroscopy (sXAS), [46][47][48] and time-of-flight secondary ion mass spectrometry (ToF-SIMS) [41] have been utilized to investigate the properties and formation mechanisms of the SEI. The electrode-electrolyte interfaces for solid-state batteries have also been experimentallyRechargeable Li-ion battery technology has progressed due to the development of a suitable combination of electroactive materials, binders, electrolytes, additives, and electrochemical cycling protocols that resulted in the formation of a stable electrode-electrolyte interphase. It is expected that Na-ion technology will attain a position comparable to Li-ion batte...

Influence of the Current Density on the Interfacial Reactivity of Layered Oxide Cathodes for Sodium‐Ion Batteries

“…[24][25][26][27] One of the reasons for the impossibility to transfer the acquired knowledge on LIB electrode-electrolyte interphases directly to SIBs is due to the differences in the SEI/CEI properties. [28,29] Among such differences, the solubility of the sodium-based species upon electrochemical cycling [30] is one of the main parameters related to the poor long-term stability and electrochemical performance of SIBs. [17] Another critical difference is related to the SEI/CEI formation mechanisms, while usually organic-rich SEI is formed in lithium-based systems, an inorganic-rich SEI is found in SIBs.…”

“…In the past years, there has been an increasing interest in the study of SIBs SEI/CEI chemistry and stability, including the correlation of the interphase properties with the electrochemical performance of the cells. [28,29] Nonetheless, additional efforts should be carried out in this field to reach the necessary improvements for boosting the commercialization of SIBs. Currently, the electrode-electrolyte interphase studies have been focused on the effect of electrode and electrolyte characteristics, [14][15][16][17][18][19][20][21][22][23][24][25][26][27] such as the electrolyte formulation, the coating of the electroactive material, and the integration of interlayers; [8,28,29] not considering other crucial parameters such as the applied current density or operating temperature.…”

“…[28,29] Nonetheless, additional efforts should be carried out in this field to reach the necessary improvements for boosting the commercialization of SIBs. Currently, the electrode-electrolyte interphase studies have been focused on the effect of electrode and electrolyte characteristics, [14][15][16][17][18][19][20][21][22][23][24][25][26][27] such as the electrolyte formulation, the coating of the electroactive material, and the integration of interlayers; [8,28,29] not considering other crucial parameters such as the applied current density or operating temperature. Indeed, cycling protocols at low current densities are typically applied to ensure the proper formation of the SEI, e.g., on hard carbon anodes, during the so-called formation cycles.…”

Na Storage Activity or Inertness of P-Configurations in N, P Dual-Doped Carbon Nanofibers: Bulk vs Surface

“…These results also confirm that PO x could inhibit the formation of Na 2 CO 3 . Compared with Na 2 O/NaF, high Na 2 CO 3 content on the surface could be harmful to electrochemical stability . As reported, phosphate additives in electrolytes could effectively promote the stability of SEI. , The surface PO x groups could play a similar role.…”

A lamellar V2O3@C composite for aluminium-ion batteries displaying long cycle life and low-temperature tolerance

“…Developing renewable energy to reduce fossil energy consumption, and to replace fuel vehicles with electric vehicles has been a growing trend globally. Among many electrochemical energy-storage systems, Li-ion batteries have a wide voltage window and have been used in many fields, 1–3 which lead to an increasing need for Li resources. 4 Considering this, it is necessary to develop emerging battery systems to reduce the requirement on Li-ion batteries.…”