From lithium to sodium: Cell chemistry of room temperature sodium-air and sodium-sulfur batteries

Research devoted to room temperature lithium–sulfur (Li/S8) and lithium–oxygen (Li/O2) batteries has significantly increased over the past ten years. The race to develop such cell systems is mainly motivated by the very high theoretical energy density and the abundance of sulfur and oxygen. The cell chemistry, however, is complex, and progress toward practical device development remains hampered by some fundamental key issues, which are currently being tackled by numerous approaches. Quite surprisingly, not much is known about the analogous sodium-based battery systems, although the already commercialized, high-temperature Na/S8 and Na/NiCl2 batteries suggest that a rechargeable battery based on sodium is feasible on a large scale. Moreover, the natural abundance of sodium is an attractive benefit for the development of batteries based on low cost components. This review provides a summary of the state-of-the-art knowledge on lithium–sulfur and lithium–oxygen batteries and a direct comparison with the analogous sodium systems. The general properties, major benefits and challenges, recent strategies for performance improvements and general guidelines for further development are summarized and critically discussed. In general, the substitution of lithium for sodium has a strong impact on the overall properties of the cell reaction and differences in ion transport, phase stability, electrode potential, energy density, etc. can be thus expected. Whether these differences will benefit a more reversible cell chemistry is still an open question, but some of the first reports on room temperature Na/S8 and Na/O2 cells already show some exciting differences as compared to the established Li/S8 and Li/O2 systems

From High to Low Temperature The Revival of Sodium Beta Alumina for Sodium Solid State Batteries

Sodium based batteries are promising post lithium ion technologies because sodium offers a specific capacity of 1166 amp; 8197;mAh amp; 8201;g amp; 8722;1 and a potential of amp; 8722;2.71 amp; 8197;V vs. the standard hydrogen electrode. The solid electrolyte sodium beta alumina shows a unique combination of properties because it exhibits high ionic conductivity, as well as mechanical stability and chemical stability against sodium. Pairing a sodium negative electrode and sodium beta alumina with Na ion type positive electrodes, therefore, results in a promising solid state cell concept. This review highlights the opportunities and challenges of using sodium beta alumina in batteries operating from medium to low temperatures 200 amp; 8201; C 20 amp; 8201; C . Firstly, the recent progress in sodium beta alumina fabrication and doping methods are summarized. We discuss strategies for modifying the interfaces between sodium beta alumina and both the positive and negative electrodes. Secondly, recent achievements in designing full cells with sodium beta alumina are summarized and compared. The review concludes with an outlook on future research directions. Overall, this review shows the promising prospects of using sodium beta alumina for the development of solid state batterie

Assessment on the Use of High Capacity “Sn4_{4}P3_{3}”/NHC Composite Electrodes for Sodium-Ion Batteries with Ether and Carbonate Electrolytes

This work reports the facile synthesis of a Sn–P composite combined with nitrogen doped hard carbon (NHC) obtained by ball-milling and its use as electrode material for sodium ion batteries (SIBs). The “Sn$_{4}$P$_{3}$”/NHC electrode (with nominal composition “Sn$_{4}$P$_{3}$”:NHC = 75:25 wt%) when coupled with a diglyme-based electrolyte rather than the most commonly employed carbonate-based systems, exhibits a reversible capacity of 550 mAh g$_{electrode}$$^{−1}$ at 50 mA g$^{−1}$ and 440 mAh g$_{electrode}$$^{−1}$ over 500 cycles (83% capacity retention). Morphology and solid electrolyte interphase formation of cycled “Sn$_{4}$P$_{3}$”/NHC electrodes is studied via electron microscopy and X-ray photoelectron spectroscopy. The expansion of the electrode upon sodiation (300 mAh g$_{electrode}$$^{−1}$) is only about 12–14% as determined by in situ electrochemical dilatometry, giving a reasonable explanation for the excellent cycle life despite the conversion-type storage mechanism. In situ X-ray diffraction shows that the discharge product is Na$_{15}$Sn$_{4}$. The formation of mostly amorphous Na$_{3}$P is derived from the overall (electro)chemical reactions. Upon charge the formation of Sn is observed while amorphous P is derived, which are reversibly alloying with Na in the subsequent cycles. However, the formation of Sn$_{4}$P$_{3}$ can be certainly excluded