Negative dielectric constant of water confined in nanosheets.

Electric double-layer capacitors are efficient energy storage devices that have the potential to account for uneven power demand in sustainable energy systems. Earlier attempts to improve an unsatisfactory capacitance of electric double-layer capacitors have focused on meso- or nanostructuring to increase the accessible surface area and minimize the distance between the adsorbed ions and the electrode. However, the dielectric constant of the electrolyte solvent embedded between adsorbed ions and the electrode surface, which also governs the capacitance, has not been previously exploited to manipulate the capacitance.

A [Fe(Tp)(CN)] scorpionate-based complex as a building block for designing ion storage hosts (Tp: hydrotrispyrazolylborate).

Using a scorpionate-based complex, [FeIII(Tp)(CN)3]-, as a building block, a new cyanide-based molecular material [{FeIII(Tp)(CN)3}2NiII(H2O)2]·4H2O (1), which can be viewed as a lower dimensional model of Prussian blue analogues, was investigated as a lithium-ion storage host.

MXene as a Charge Storage Host.

The development of efficient electrochemical energy storage (EES) devices is an important sustainability issue to realize green electrical grids. Charge storage mechanisms in present EES devices, such as ion (de)intercalation in lithium-ion batteries and electric double layer formation in capacitors, provide insufficient efficiency and performance for grid use. Intercalation pseudocapacitance (or redox capacitance) has emerged as an alternative chemistry for advanced EES devices.

A new rechargeable sodium battery utilizing reversible topotactic oxygen extraction/insertion of CaFeO(z) (2.5 ≤ z ≤ 3) in an organic electrolyte.

At present, significant research efforts are being devoted both to identifying means of upgrading existing batteries, including lithium ion types, and also to developing alternate technologies, such as sodium ion, metal-air, and lithium-sulfur batteries. In addition, new battery systems incorporating novel electrode reactions are being identified. One such system utilizes the reaction of electrolyte ions with oxygen atoms reversibly extracted and reinserted topotactically from cathode materials.