Abstract: Electrochemical energy storage devices are provided comprising an anode, a cathode and a solid-state electrolyte adapted for Na-ion conduction between the anode and cathode. The solid-state electrolyte includes, for example, a solid solution of doped NaAlO2 having a composition defined by one of Dx(NaAlO2)1-x in which D is at least one of GeO2, SnO2, TiO2, ZrO2 and HfO2, and Dx/2(NaAlO2)1-x in which D is PAlO4, where 0<x?0.5. Other solid-state electrolyte compositions are also disclosed.

Abstract: An electrochemical energy storage device is provided. The device may include a solid-state anode layer. The device may comprise a solid-state electrolyte layer. Further, the device may comprise a solid-state cathode layer. At least two adjacent ones out of the solid-state anode layer, the solid-state electrolyte layer, and the solid-state cathode layer may form a solid-state single-crystal with varying chemical compositions between the related layers. The solid-state electrolyte layer may have an ionic conductivity at room temperature higher than 10?6 S/cm.

Abstract: An electrochemical energy storage device is provided. The device may include a solid-state anode layer. The device may comprise a solid-state electrolyte layer. Further, the device may comprise a solid-state cathode layer. At least two adjacent ones out of the solid-state anode layer, the solid-state electrolyte layer, and the solid-state cathode layer may form a solid-state single-crystal with varying chemical compositions between the related layers. The solid-state electrolyte layer may have an ionic conductivity at room temperature higher than 10?6 S/cm.

Abstract: A membrane electrode assembly for an electrochemical cell, in particular a co-electrolysis cell for CO2 reduction reaction, can overcome the problem of parasitic CO2 pumping from cathode to anode side and, at the same time, maintain good Faradaic efficiency towards CO2 reduction reaction in a co-electrolysis system where pure or diluted gaseous CO2 is used. The assembly includes an MEA, having an anode, a cathode, a polymer ion exchange membrane between cathode and anode, an additional ion exchange polymer film between the cathode and the polymer ion exchange membrane and a discontinuous interface formed between the additional polymer film located at the cathode side and the ion exchange membrane.

Abstract: Electrochemical energy storage devices are provided comprising an anode, a cathode and a solid-state electrolyte adapted for Na-ion conduction between the anode and cathode. The solid-state electrolyte includes, for example, a solid solution of doped NaAlO2 having a composition defined by one of Dx(NaAlO2)1-x in which D is at least one of GeO2, SnO2, TiO2, ZrO2 and HfO2, and Dx/2(NaAlO2)1-x in which D is PAlO4, where 0<x?0.5. Other solid-state electrolyte compositions are also disclosed.