Aqueous Electrolytes for Redox Flow Battery Systems
All-vanadium Redox Flow Battery Based on Supporting Solutions Containing Chloride
SEASONAL ENERGY STORAGE TECHNOLOGIES BASED ON RECHARGEABLE BATTERIES
The present invention reports a method for constructing a temperature activated rechargeable battery and apply the device for seasonal electrical energy storage. The battery consists of a metal anode, a metal cathode, a molten salt electrolyte, and a porous separator (Figure 1). The battery operates at an elevated temperature during charging and discharging, at which the molten salt electrolyte is in a liquid state. During idling, the battery will be kept at ambient temperature, and capacity loss due to self-discharge is minimized by freezing the electrolytes.
Graphene-Based Battery Electrodes Having Continuous Flow Paths
Some batteries can exhibit greatly improved performance by utilizing electrodes having randomly arranged graphene nanosheets forming a network of channels defining continuous flow paths through the electrode. The network of channels can provide a diffusion pathway for the liquid electrolyte and/or for reactant gases. Metal-air batteries can benefit from such electrodes. In particular Li-air batteries show extremely high capacities, wherein the network of channels allow oxygen to diffuse through the electrode and mesopores in the electrode can store discharge products.
SOLID-STATE RECHARGEABLE MAGNESIUM BATTERY
Embodiments of a solid-state electrolyte comprising magnesium borohydride, polyethylene oxide, and optionally a Group IIA or transition metal oxide are disclosed. The solid-state electrolyte may be a thin film comprising a dispersion of magnesium borohydride and magnesium oxide nanoparticles in polyethylene oxide. Rechargeable magnesium batteries including the disclosed solid-state electrolyte may have a coulombic efficiency ≧95% and exhibit cycling stability for at least 50 cycles.
GRAPHENE-SULFUR NANOCOMPOSITES FOR RECHARGEABLE LITHIUM-SULFUR BATTERY ELECTRODES
Rechargeable lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter less than 50 nm.
Graphene-Sulfur Nanocomposites for Rechargeable Lithium-Sulfur Battery Electrodes
Rechargeable lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter less than 50 nm.
HIGH EFFICIENCY ELECTROLYTES FOR HIGH VOLTAGE BATTERY SYSTEMS
This invention is the design of a high efficiency electrolyte that enables the stable cycling of lithium cobalt oxide (LiCoO2, or LCO) layered cathode under high voltages (e.g. 4.5 V vs. Li/Li+). Due to the structural instability of LCO cathode materials under high voltages ( > 4.2 V), commercial Li-ion batteries (LIBs) using LCO cathode typically has a low cut-off charge voltage. The practical reversible capacity of LCO is only limited to ~140 mAh g-1. Nevertheless, in this new electrolyte, the LCO cathode could deliver a very high capacity about 190 mAh g-1 (at 0.1C) and realize excellent cycling stability under a charge cut-off voltage of 4.5 V, along with a cell Coulombic efficiency (CE) over 99.8%. In sharp contrast, in the conventional carbonate electrolyte (1 M LiPF6 in EC/EMC, 3:7 wt), the LCO cathode has a fast capacity fading (66% capacity retention after only 50 cycles) and a low cell CE about 97.5%. Therefore, this new electrolyte could significantly improve the energy densities and cycle lives of batteries with LCO cathodes.
All-Vanadium Pure Sulfate Redox Flow Battery Electrolytes and Cell Stack Designs
Nanocomposite protective coatings for battery anodes
Modified surfaces on metal anodes for batteries can help resist formation of malfunction-inducing surface defects. The modification can include application of a protective nanocomposite coating that can inhibit formation of surface defects. such as dendrites, on the anode during charge/discharge cycles. For example, for anodes having a metal (M′), the protective coating can be characterized by products of chemical or electrochemical dissociation of a nanocomposite containing a polymer and an exfoliated compound (Ma′Mb″Xc). The metal, M′, comprises Li, Na, or Zn. The exfoliated compound comprises M′ among lamella of Mb″Xc, wherein M″ is Fe, Mo, Ta, W, or V, and X is S, O, or Se.