Redox flow battery efficiency and performance may be improved with a high energy density bipyridinium based ionic room-temperature liquid electrolyte. Current electrolytes require solvent to dissolve the redox-active material and a supporting electrolyte to maintain charge balance. A room temperature redox-active electrolyte having intrinsic charge balancing would not need a solvent to form a liquid and would therefore have a higher density of anions and cations involved with charge storage. As such, creating redox-active bipyridinium core ionic materials that are in a liquid form at room temperature or, more particularly, are liquids across the range at which a redox flow battery would operate permit smaller and less costly flow battery design than conventional flow batteries.

A battery includes a fluid negative electrode and a fluid positive electrode separated by a solid electrolyte at least when the electrodes and electrolyte are at an operating temperature. The solid electrolyte comprises a salt formed by ions of the negative electrode material forming the fluid negative electrode. In one example, the fluid negative electrode comprises lithium (Li), the fluid positive electrode comprises sulfur (S) and the solid electrolyte comprises lithium iodide (LiI).

We disclose quinone compounds and related species (Formula I) that possess significant advantages when used as a redox active material in a battery, e.g., a redox flow battery. In particular, the compounds provide redox flow batteries (RFBs) with extremely high capacity retention. For example, RFBs of the invention can be cycled for 500 times with negligible loss of capacity, and such batteries could be employed for years of service. Thus, the invention provides a high efficiency, long cycle life redox flow battery with reasonable power cost, low energy cost, and all the energy scaling advantages of a flow battery. ##STR00001##

Polymers of intrinsic microporosity are provided herein. Disclosed polymers of intrinsic microporosity include modified polymers of intrinsic microporosity that include negatively charged sites or crosslinking between monomer units. Systems making use of polymers of intrinsic microporosity and modified polymers of intrinsic microporosity are also described, such as electrochemical cells and ion separation systems. Methods for making and using polymers of intrinsic microporosity and modified polymers of intrinsic microporosity are also disclosed.

A method for determining a storage capacity or average oxidation state (AOS) of a redox flow battery system including an anolyte and a catholyte includes discharging a portion of the anolyte and catholyte of the redox flow battery system at a discharge rate that is within 10% of a preselected discharge rate; after discharging the redox flow battery system, determining an end OCV; and determining the storage capacity or AOS from the end OCV. Other methods can be used to determine the storage capacity or AOS using a measured OCV.

A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

A redox flow battery for storing electrical energy is described, comprising a reaction cell with two electrode chambers for catholyte and anolyte, each of which is connected to at least one liquid reservoir, the electrode chambers being separated by a membrane, being equipped with electrodes, and each being filled with electrolyte solutions which contain redox-active components dissolved or dispersed in an aqueous electrolyte solvent, as well as conducting salts dissolved therein and possibly further additives. A second embodiment relates to a redox flow battery for storing electrical energy, comprising a reaction cell with an electrode chamber for an electrolyte solution, which is connected to at least one liquid reservoir, the electrode chamber being equipped with a cathode and an anode, and being filled with electrolyte solution which contains redox-active components dissolved or dispersed in an aqueous electrolyte solvent, as well as conductive salts dissolved therein and possibly further additives. The redox flow cells are characterized in that the at least one liquid reservois is an underground storage means in which temperatures of at least 30° C. prevail, in that the concentration of the salts dissolved in the electrolyte solutions is at least 10% by weight, and in that the catholyte or the electrolyte solution contains selected redox-active and temperature-stable components. In the first embodiment, the anolyte contains a water-soluble redox-active component and in the second embodiment, the anolyte or the electrolyte solution contains a zinc salt.

A redox flow battery includes a negative electrode; a positive electrode; a first liquid which contains a first nonaqueous solvent, a first redox species, and metal ions and which is in contact with the negative electrode; a second liquid which contains a second nonaqueous solvent and which is in contact with the positive electrode; and a metal ion-conducting membrane which is disposed between the first liquid and the second liquid and which is nonporous. The metal ion-conducting membrane is swollen by at least one selected from the group consisting of the first liquid and the second liquid and allows the metal ions to pass therethrough.

A primary electrochemical cell including a cell housing, an anode including metallic lithium, a liquid SOCl.sub.2 cathode and a separator separating the anode from the cathode. The liquid SOCl.sub.2 cathode material includes a salt of a Lewis base with a Lewis acid dissolved in the SOCl.sub.2 to form an electrolyte solution and an amount of SnCl.sub.2 dissolved in the electrolyte solution. The cell has a higher TMV and lower cell impedance after extended periods of cell storage at room or higher temperatures as compared to similar prior art primary Li/SOCl.sub.2 cells that do not include the SnCl.sub.2 additive.

The present disclosure relates to electrodes comprising a polymer film and a substrate, wherein the polymer film has a thickness of about 5 nm to about 600 nm. The present disclosure also relates to electrochemical cells and batteries comprising the electrodes disclosed herein. The present disclosure also relates to methods of making the electrodes disclosed herein.