A new polyelectrolyte multilayer coated proton-exchange membrane for electrolysis and fuel cell applications has been developed for electrolysis and fuel cell applications. The polyelectrolyte multilayer coated proton-exchange membrane comprises: a cation exchange membrane, and a polyelectrolyte multilayer coating on one or both surfaces of the cation exchange membrane. The polyelectrolyte multilayer coating comprises alternating layers of a polycation polymer and a polyanion polymer. The polycation polymer layer is deposited on and is in contact with the cation exchange membrane. The top layer of the polyelectrolyte multilayer coating can be either a polycation polymer layer or a polyanion polymer layer.

Provided is an LDH separator including a porous substrate and a mixture of a layered double hydroxide (LDH)-like compound and In(OH).sub.3, which fills up pores of the porous substrate. The LDH-like compound is a hydroxide and/or an oxide with a layered crystal structure containing Mg, Ti, Y, and optionally Al and/or In.

Provided is an LDH separator including a porous substrate and a mixture of a layered double hydroxide (LDH)-like compound and In(OH).sub.3, which fills up pores of the porous substrate. The LDH-like compound is a hydroxide and/or an oxide with a layered crystal structure containing Mg, Ti, Y, and optionally Al and/or In.

A redox flow battery includes: a negative electrode; a positive electrode; a first liquid which is in contact with the negative electrode, and which contains a first nonaqueous solvent, a first redox species, and metal ions; a second liquid which is in contact with the positive electrode, and which contains a second nonaqueous solvent, a second redox species, and metal ions; and a metal ion-conducting membrane disposed between the first liquid and the second liquid. The metal ion-conducting membrane contains an organic polymer containing a plurality of hydroxy groups. The organic polymer contains a group formed by substituting at least a portion of the hydroxy groups with a metal sulfonate.

Disclosed are a hybrid solid electrolyte sheet and a method of manufacturing the same. The hybrid solid electrolyte sheet includes a hybrid solid electrolyte layer including a gel polymer electrolyte, thereby securing flexibility and alleviating brittleness. In addition, the hybrid solid electrolyte sheet includes a porous polymer film having a plurality of pores, thus minimizing the content of the acrylate monomer in the pores thereof and providing advantages of maintaining the continuity of the solid electrolyte while minimizing a decrease in ionic conductivity.

A composition of matter, has a solid foam, at least one ionic conductor in the foam, and an electronic conductor in the foam. A battery has an anode, comprising a metal electrode and a solid foam, a cathode, and a solid electrolyte between the anode and the cathode, the solid electrolyte in contact with the solid foam. A solid foam has an electronic conductor, a hard ionic conductor, and a soft ionic conductor.

A solid-state battery cell includes a cathode region, an anode region, a separator interconnecting the cathode region and the anode region, a cathode current collector on a surface of the cathode region, an anode current collector on a surface of the anode region, a first piezoelectric layer on a surface of the cathode current collector, and a second piezoelectric layer on a surface of the anode current collector. A method of operating a solid-state battery cell includes detecting a material change in the anode or the cathode, applying a voltage to the first piezoelectric material layer or the second piezoelectric material layer, and generating a pressure against the cathode current collector or the anode current collector by the first piezoelectric material layer or the second piezoelectric material layer, the pressure being generated as a result of the applied voltage.

A nanocomposite membrane includes a polymer phase, a nanowire phase, and a pore phase. The polymer phase includes a polymer including a cyclic imide group. The nanowire phase includes metal oxide nanowires. Each of the polymer phase and the nanowire phase is uniformly distributed within at least part of the nanocomposite membrane.

A nanocomposite membrane includes a polymer phase, a nanowire phase, and a pore phase. The polymer phase includes a polymer including a cyclic imide group. The nanowire phase includes metal oxide nanowires. Each of the polymer phase and the nanowire phase is uniformly distributed within at least part of the nanocomposite membrane.

Embodiments of the present disclosure include solid-state electrolytes comprising a porous host and solid polymer electrolyte fillers dispersed within pores of the porous host. Further embodiments include batteries comprising an anode, a cathode, and a solid-state electrolyte of the disclosure disposed between the anode and the cathode.