Provided is an active material for a fluoride-ion secondary battery, the active material containing a composite fluoride. The composite fluoride has a layered structure and is represented by a composition formula A.sub.mM.sub.nF.sub.x, where A is an alkali metal, M is a transition metal, 0<m≤2, 1≤n≤2, and 3≤x≤4. The alkali metal may be at least one kind selected from the group consisting of Na, K, Rb, and Cs. The transition metal may be a 3d transition metal.

The system of the present invention includes a conductive element, an electronic component, and a partial power source in the form of dissimilar materials. Upon contact with a conducting fluid, a voltage potential is created and the power source is completed, which activates the system. The electronic component controls the conductance between the dissimilar materials to produce a unique current signature. The system can also measure the conditions of the environment surrounding the system.

The present disclosure relates to a method of making core-shell and yolk-shell nanoparticles, and to electrodes comprising the same. The core-shell and yolk-shell nanoparticles and electrodes comprising them are suitable for use in electrochemical cells, such as fluoride shuttle batteries. The shell may protect the metal core from oxidation, including in an electrochemical cell. In some embodiments, an electrochemically active structure includes a dimensionally changeable active material forming a particle that expands or contracts upon reaction with or release of fluoride ions. One or more particles are at least partially surrounded with a fluoride-conducting encapsulant and optionally one or more voids are formed between the active material and the encapsulant using sacrificial layers or selective etching. When the electrochemically active structures are used in secondary batteries, the presence of voids can accommodate dimensional changes of the active material.

A rechargeable metal halide battery shows increased metal halide utilization with the introduction of electronegative heteroatom-enriched conductive additives into a metal halide cathode incorporated into an electrically conductive material. The electronegative heteroatom-enriched conductive additives include nitrogen-doped carbon, such as nitrogen-doped single layer graphene, and oxygen-enriched carbon, such as acid-treated carbon black. The modified batteries utilize 20-30% more metal halide than unmodified batteries resulting in enhanced specific capacity and energy density.

A rechargeable metal halide battery with an optimized electrolyte formulation shows high capacity at fast charging rates. The optimized electrolyte includes a metal halide, an oxidizing gas, and a mixed-solvent solution that includes a glyme-based compound that is in a volume fraction of between 20-70 volume % of the mixed-solvent solution. The mixed-solvent solution may further include a nitrile compound and/or a heterocyclic compound.

A battery electrode composition is provided that comprises composite particles. Each of the composite particles in the composition (which may represent all or a portion of a larger composition) may comprise a porous electrode particle and a filler material. The porous electrode particle may comprise active material provided to store and release ions during battery operation. The filler material may occupy at least a portion of the pores of the electrode particle. The filler material may comprise a solid and is not substantially conductive with respect to electron transport.

Composite particles and a negative electrode active material including such particles for an electrochemical device. The negative electrode active material is capable of lithium intercalation/deintercalation and includes composite particles including a carbon phase including a carbonaceous material, silicon (Si) and lithium fluoride (LiF). The Si and LiF may be present as Si—LiF mixed particles, which are dispersed in the carbon phase, wherein the Si—LiF mixed particles are dispersed in the carbon phase with uniform or non-uniform distribution. In addition, the composite particles include the carbon phase mixed uniformly or amorphously with the Si—LiF mixed particles.

An electrode comprises an electrode core. A composite bilayer coating is conformally disposed on the electrode core. The composite bilayer coating comprises a first layer disposed on at least a portion of the electrode core. The first layer comprises a metal fluoride, a metal oxide or a metal sulfide. A second layer is disposed on the first layer and comprises a metal fluoride, a metal oxide or a metal sulfide.

An enhanced solid state battery cell is disclosed. The battery cell can include a first electrode, a second electrode, and a solid state electrolyte layer interposed between the first electrode and the second electrode. The battery cell can further include a resistive layer interposed between the first electrode and the second electrode. The resistive layer can be electrically conductive in order to regulate an internal current flow within the battery cell. The internal current flow can result from an internal short circuit formed between the first electrode and the second electrode. The internal short circuit can be formed from the solid state electrolyte layer being penetrated by metal dendrites formed at the first electrode and/or the second electrode.

The positive electrode active substance for a lithium secondary battery includes a mixture of a lithium cobalt composite oxide particle and an inorganic fluoride particle. The method for producing a positive electrode active substance for a lithium secondary battery includes a first step of subjecting a lithium cobalt composite oxide particle and an inorganic fluoride particle to a mixing treatment to thereby obtain a mixture of the lithium cobalt composite oxide particle and the inorganic fluoride particle. The lithium secondary battery uses, as a positive electrode active substance, the positive electrode active substance for a lithium secondary battery of the present invention.