Anodic Activity of Hydrated and Anhydrous Iron (II) Oxalate in Li-Ion Batteries

We discuss the applicability of the naturally occurring compound Ferrous Oxalate Dihydrate (FOD) (FeC2O4·2H2O) as an anode material in Li-ion batteries. Using first-principles modeling, we evaluate the electrochemical activity of FOD and demonstrate how its structural water content affects the intercalation reaction and contributes to its performance. We show that both Li0 and Li+ intercalation in FOD yields similar results. Our analysis indicates that fully dehydrated ferrous oxalate is a more promising anodic material with higher electrochemical stability: it carries 20% higher theoretical Li storage capacity and a lower voltage (0.68 V at the PBE/cc-pVDZ level), compared to its hydrated (2.29 V) or partially hydrated (1.43 V) counterparts.

A universal graphitic interlayered centroid intercalation theory for intercalation chemistry

Neither of the two widely used staging models in the long history of intercalation chemistry, namely the classical Rüdorff-Hofmann model proposed in 1938 and the pleated-layer domain-modified one in 1969, can explain the intercalation reaction phenomena and mechanism logically. Taking the landmark potassium-intercalation reaction of graphite as a model case and two advanced monolithic graphitic/graphenic carbon foams as model electrodes, here we have revealed that the electrochemical storage of potassium in graphitic/graphenic carbon (as that of lithium) obeys a simple interlayered centroid intercalation (ICIC) rule to achieve the staged potassium intercalation into each graphitic interlayer: C → KC72 → KC24 → KC8. Moreover, judging from the typical potassium-storage behaviors and crystal texture of graphitic electrodes, nitrogen doping and pre-embedded K atoms would enable incoming K+ ions to perform fast pseudocapacitive diffusion in graphitic gallery. This study not only makes clear the basic K-storage mechanism and phenomena in graphitic carbon, but also establishes a more reasonable ICIC model for intercalation chemistry, and thus may help open a new research era for this field as well as graphite-based metal-ion batteries.

Nano Hard Carbon Anodes for Sodium-Ion Batteries

A hindrance to the practical use of sodium-ion batteries is the lack of adequate anode materials. By utilizing the co-intercalation reaction, graphite, which is the most common anode material of lithium-ion batteries, was used for storing sodium ion. However, its performance, such as reversible capacity and coulombic efficiency, remains unsatisfactory for practical needs. Therefore, to overcome these drawbacks, a new carbon material was synthesized so that co-intercalation could occur efficiently. This carbon material has the same morphology as carbon black; that is, it has a wide pathway due to a turbostratic structure, and a short pathway due to small primary particles that allows the co-intercalation reaction to occur efficiently. Additionally, due to the numerous voids present in the inner amorphous structure, the sodium storage capacity was greatly increased. Furthermore, owing to the coarse co-intercalation reaction due to the surface pore structure, the formation of solid-electrolyte interphase was greatly suppressed and the first cycle coulombic efficiency reached 80%. This study shows that the carbon material alone can be used to design good electrode materials for sodium-ion batteries without the use of next-generation materials.

Exploring the high-voltage Mg2+/Na+ co-intercalation reaction of Na3VCr(PO4)3 in Mg-ion batteries

A Na3VCr(PO4)3 cathode facilitates a high voltage Mg2+/Na+ co-intercalation reaction entailing V3+/V4+ and V4+/V5+ redox couples at 1.7–2.3 V vs. Mg2+/Mg.

Thermodynamic Parameters of the Intercalation Reaction in Thermal and Laser Modified Nanodispersed Anatase

It is modified matrix of anatase in turn of the thermal and laser treatments. Thedependence of Gibbs energy change of the intercalation reaction of lithium with the guest loaddegree change was analyzed. Laser irradiation turned out to increase twice the value of maximumlithium “guest” loading, constricting heterophase area and changing contrarily concentrationgenesis of temperature dependence of entropy of lithium dilution. The optimal conditions of laserirradiation nanodispersive anatase (pulse energy E = 0,02 J, pulse duration τ = 15 ns repetitionfrequency f = 28 Hz, duration of exposure to 5 min.), at which specific energy characteristics of LPS,formed on its basis, increased by 55% is set