CN-116529297-B - Ion conductive thin film composite membranes for energy storage applications

Abstract

An ion conductive Thin Film Composite (TFC) membrane is described. The low cost, high performance TFC membrane includes a microporous support membrane, and a hydrophilic ionomer coating on a surface of the microporous support membrane. The hydrophilic ionic polymer coating is ion conductive. The ionomer may also be present in the micropores of the support membrane. Methods of making the membranes and redox flow battery systems incorporating TFC membranes are also described.

Inventors

• LIU CHUNQING
• DONG XUELIANG
• BA CHAOYI

Assignees

• 环球油品有限责任公司

Dates

Publication Date

20260508

Application Date

20211102

Priority Date

20201104

Claims (7)

1. 1. An ion conductive Thin Film Composite (TFC) membrane, the TFC membrane comprising: Microporous support films based on polyolefin; A water insoluble hydrophilic ionic polymer coating on the surface of the microporous support membrane, the water insoluble hydrophilic ionic polymer coating being ion conductive, wherein the water insoluble hydrophilic ionic polymer comprises a polysaccharide polymer complexed with polyphosphoric acid and iron metal ions, or a polysaccharide polymer complexed with iron metal ions.
2. 2. The TFC membrane of claim 1, wherein the polysaccharide polymer comprises chitosan, sodium alginate, alginic acid, hyaluronic acid, dextran, pullulan, carboxymethyl curdlan, pectic acid, chitin, chondroitin, xanthan gum, or a combination thereof.
3. 3. The TFC membrane of claim 1, wherein the support membrane comprises polyethylene, polypropylene, or a combination thereof.
4. 4. The TFC membrane of claim 1, wherein the water-insoluble hydrophilic ionic polymer is present in micropores of the support membrane.
5. 5. A method of preparing the ion conductive Thin Film Composite (TFC) membrane of claim 1, the method comprising: Applying an aqueous solution layer comprising a water-soluble hydrophilic polymer to one surface of a polyolefin-based microporous support membrane; drying the coated film; Complexing the hydrophilic polymer with a complexing agent to form a water insoluble hydrophilic ionic polymer, wherein the water soluble hydrophilic polymer on the coated film is dried prior to complexing the hydrophilic polymer, or wherein the coated film is dried after complexing the hydrophilic polymer.
6. 6. The method of claim 5, wherein complexing the hydrophilic polymer comprises immersing the dried coated membrane in a second aqueous solution of polyphosphoric acid, boric acid, a metal salt, hydrochloric acid, or a combination thereof, or complexing the dried coated membrane in situ with a complexing agent in a redox flow battery cell.
7. 7. A redox flow battery system comprising at least one rechargeable battery comprising a positive electrolyte, a negative electrolyte, and an ion-conductive Thin Film Composite (TFC) membrane positioned between the positive electrolyte and the negative electrolyte, wherein the TFC membrane comprises the TFC membrane of claim 1.

Description

Ion conductive thin film composite membranes for energy storage applications Priority statement The present application claims priority from U.S. provisional patent application Ser. No. 63/109,683, filed 11/4/2020, which is incorporated herein by reference in its entirety. Background Energy storage systems play a critical role in collecting energy from a variety of sources. Energy storage systems may be used to store energy and convert it for use in many different applications, such as construction, transportation, public service, and industry. A variety of energy storage systems have been used commercially and new systems are currently being developed. The energy storage types can be categorized as electrochemical and battery, thermal, thermochemical, flywheel, compressed air, pumped storage, magnetic, biological, chemical and hydrogen energy storage. There is a need to develop cost-effective and eco-friendly energy storage systems to address energy crisis and to overcome the mismatch between power generation and end use. Renewable energy sources, such as wind and solar energy, have transient characteristics that require energy storage. Renewable energy storage systems such as Redox Flow Batteries (RFBs) have attracted significant attention for electrical grids, electric vehicles, and other large scale stationary applications. RFB is an electrochemical energy storage system that directly and reversibly converts chemical energy into electricity. The combination of electricity, chemistry, transportation and heating sectors is achieved by the electrolysis of water to convert electricity into hydrogen as an energy carrier without producing carbon monoxide or carbon dioxide as by-products. Water electrolysis produces high quality hydrogen by the electrochemical decomposition of water into hydrogen and oxygen. When the method is operated by renewable energy sources such as wind, solar or geothermal energy, the water electrolysis has a zero carbon footprint. The primary water electrolysis techniques include alkaline electrolysis, polymer Electrolyte Membrane (PEM) electrolysis, and solid oxide electrolysis. PEM water electrolysis is one of the advantageous methods of converting renewable energy sources to high purity hydrogen and has the advantages of compact design, high current density, high efficiency, fast response, small footprint, low temperature (20-90 ℃) operation, and high purity oxygen byproduct. RFB consists of two tanks filled with active material containing metal ions that can be in different valence states, two circulation pumps and a flow cell with a separation membrane. A separation membrane is located between the anode and the cathode and serves to separate the anolyte and the catholyte and to utilize the current loop by allowing transfer of counter ions. Among all redox flow batteries developed so far, all Vanadium Redox Flow Batteries (VRFB) have been most widely studied. VRFB uses the same vanadium element in both half cells, which prevents osmotic contamination of the electrolyte from one half cell to the other. However, VRFB is inherently expensive due to the use of high cost vanadium and expensive membranes. Full iron redox flow batteries (IFBs) are particularly attractive for grid scale storage applications due to the use of low cost iron, salts and water as electrolytes. Membranes are one of the key materials that make up batteries or cells, as a key driver of safety and performance. Some important characteristics of membranes for flow batteries, fuel cells and membrane electrolysis include high conductivity, high ion permeability (porosity, pore size and pore size distribution), high ion exchange capacity (for ion exchange membranes), high ion/electrolyte selectivity (low permeability/permeation to electrolyte), low cost (less than $150/m 2-$200/m2), low area resistance to minimize efficiency losses due to ohmic polarization, high tolerance to oxidation and reduction conditions, chemical inertness to a wide pH range, high thermal stability along with high proton conductivity (greater than or equal to 120 ℃, for fuel cells), high proton conductivity at high T without H 2 O, high proton conductivity at high T with high RH maintained, and high mechanical strength (thickness, low swelling). Two major types of membranes used in redox flow batteries, fuel cells and electrolysis applications are polymeric ion exchange membranes and microporous separators. The polymeric ion exchange membrane may be a cation exchange membrane comprising-SO 3-、-COO-、-PO32-、-PO3H- or-C 6H4O- cation exchange functionality, an anion exchange membrane comprising-NH 3+、-NRH2+、-NR2H+、-NR3+ or-SR 2- anion exchange functionality, or a bipolar membrane comprising both a cation exchange polymer and an anion exchange polymer. The polymer used to prepare the ion exchange membrane may be a perfluorinated ionomer, such asAnd-F, a partially fluorinated polymer, a non-fluorinated hydrocarbon polymer, a non-fluorinated polymer hav