Flexible fuel cell sensors and methods of making and using the same are provided. A fuel cell sensor can be used for the detection of, for example, isopropyl alcohol (IPA), and the working mechanism of the fuel cell sensor can rely on redox reactions. The fuel cell sensor can include a proton exchange membrane (PEM), an anode disposed on a first surface of the PEM, a cathode disposed on a second surface of the PEM opposite from the first surface, and a reference electrode disposed on the first surface of the PEM and spaced apart from the anode.

The adhesion between metal foil serving as a current collector and a negative electrode active material is increased to enable long-term reliability. An electrode active material layer (including a negative electrode active material or a positive electrode active material) is formed over a base, a metal film is formed over the electrode active material layer by sputtering, and then the base and the electrode active material layer are separated at the interface therebetween; thus, an electrode is formed. The electrode active material particles in contact with the metal film are bonded by being covered with the metal film formed by the sputtering. The electrode active material is used for at least one of a pair of electrodes (a negative electrode or a positive electrode) in a lithium-ion secondary battery.

Various methods and apparatus relating to three-dimensional battery structures and methods of manufacturing them are disclosed and claimed. In certain embodiments, a three-dimensional battery comprises a battery enclosure, and a first structural layer within the battery enclosure, where the first structural layer has a first surface, and a first plurality of conductive protrusions extend from the first surface. A first plurality of electrodes is located within the battery enclosure, where the first plurality of electrodes includes a plurality of cathodes and a plurality of anodes, and wherein the first plurality of electrodes includes a second plurality of electrodes selected from the first plurality of electrodes, each of the second plurality of electrodes being in contact with the outer surface of one of said first plurality of conductive protrusions. Some embodiments relate to processes of manufacturing energy storage devices with or without the use of a backbone structure or layer.

In certain embodiments, a method includes forming a battery electrode on a substrate. Forming the battery electrode on the substrate includes depositing a first electrode active material layer on a first portion of a surface of the substrate and depositing, to form a current collector, a conductive material using a thin film deposition process on a surface of the first electrode active material layer. The conductive material is deposited over an edge of the first electrode active material layer and onto a second portion of the surface of the substrate, the second portion of the substrate being adjacent to the first portion of the substrate. The method includes removing the battery electrode from the substrate, the battery electrode including the first electrode active material layer and the current collector.

Disclosed is a negative electrode current collector for an anode-free lithium metal battery. The negative electrode current collector includes a PdTe.sub.2 layer and an intermediate layer to inhibit the growth of lithium dendrite, resulting in significant improves in lifespan and performance of the lithium metal battery. The negative electrode current collector further includes an ion conductive layer to improve the performance of the lithium metal battery.

A composite nanoarchitecture unit is disclosed. The unit comprises a columnar film grown on top of another layer where the columns touch each other at the top forming arches having optimized characteristics. This nanoarchitecture unit, called nano-vault, achieves high mechanical stability for films under strong and variable stress action.

The adhesion between metal foil serving as a current collector and a negative electrode active material is increased to enable long-term reliability. An electrode active material layer (including a negative electrode active material or a positive electrode active material) is formed over a base, a metal film is formed over the electrode active material layer by sputtering, and then the base and the electrode active material layer are separated at the interface therebetween; thus, an electrode is formed. The electrode active material particles in contact with the metal film are bonded by being covered with the metal film formed by the sputtering. The electrode active material is used for at least one of a pair of electrodes (a negative electrode or a positive electrode) in a lithium-ion secondary battery.

Disclosed is a transparent anode thin film comprising a transparent anode active material layer, wherein the transparent anode active material layer comprises a Si-based anode active material having a composition represented by the following [Chemical Formula 1]:
SiN.sub.x  [Chemical Formula 1] (wherein 0<x≤1.5).

Hybrid electrodes for batteries are disclosed having a protective electrochemically active layer on a metal layer. Other hybrid electrodes include a silicon salt on a metal electrode. The protective layer can be formed directly from the reaction between the metal electrode and a metal salt in a pre-treatment solution and/or from a reaction of the metal salt added in an electrolyte so that the protective layer can be formed in situ during battery formation cycles.

A protected anode, an electrochemical device including the same, and a method of preparing the electrochemical device. The protected anode may include: an anode layer; and a protective layer including an oxide represented by Formula 1, on the anode layer:

##STRFormula 1##

In Formula 1, A is at least one of Ge, Sb, Bi, Se, Sn, or Pb; M is at least one of In, Tl, Sb, Bi, S, Se, Te, or Po; A and M are different from each other; and 0<x<100 and 0<y<100.