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Novel Phosphazene Compounds for Enhancing Electrolyte Stability and Safety of Lithium-ion Cells

Inorganic electrolyte additives

Idaho National Laboratory

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Technology Marketing Summary

Safety and longevity of Li-ion batteries continues to be an issue for an ever expanding number applications ranging from personal electronics to electric drive vehicles. This is complicated by the push toward higher voltage cells (5V+). For over a decade there have been many reports of studies directed at decreasing the flammability of Li-ion electrolyte. However, there is still no commercially available low-flammability electrolyte that has competitive transport properties fur use in today's Li-ion battery systems.


Researchers at INL have developed new classes of novel compounds for use in Li-ion batteries. The INL suite of phosphazene materials aimed at battery electrolytes has grown to include fluorinated and ionic liquid compounds. Thermal Stability testing has been completed on initial electrolyte blends containing small amounts of INL phosphazene additives. Results conclusively demonstrate that INL additives provide significant stabilization of the baseline electrolyte. This behavior could prolong battery life and enable sustained operation at elevated temperatures.  


Inherently stable and non-flammable

Very low vapor pressure

Choice of R groups (pendant arms) has a profound influence on properties

Good lithium salt dissolution

More Information

DOE Merit Review presentation

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 6,146,787
Solid polymer battery electrolyte and reactive metal-water battery
In one implementation, a reactive metal-water battery includes an anode comprising a metal in atomic or alloy form selected from the group consisting of periodic table Group 1A metals, periodic table Group 2A metals and mixtures thereof. The battery includes a cathode comprising water. Such also includes a solid polymer electrolyte comprising a polyphosphazene comprising ligands bonded with a phosphazene polymer backbone. The ligands comprise an aromatic ring containing hydrophobic portion and a metal ion carrier portion. The metal ion carrier portion is bonded at one location with the polymer backbone and at another location with the aromatic ring containing hydrophobic portion. The invention also contemplates such solid polymer electrolytes use in reactive metal/water batteries, and in any other battery.
Idaho National Laboratory 11/14/2000
Application 20140342240
Fluorinated phosphazenes for use as electrolyte additives and co-solvents in lithium ion batteries
An electrolyte solution for use in a battery includes at least: an ionizable salt; at least one organic solvent; and at least one cyclic phosphazene compound.
Idaho National Laboratory 05/14/2014
Patent 7,008,564
Cured composite materials for reactive metal battery electrolytes
A solid molecular composite polymer-based electrolyte is made for batteries, wherein silicate compositing produces a electrolytic polymer with a semi-rigid silicate condensate framework, and then mechanical-stabilization by radiation of the outer surface of the composited material is done to form a durable and non-tacky texture on the electrolyte. The preferred ultraviolet radiation produces this desirable outer surface by creating a thin, shallow skin of crosslinked polymer on the composite material. Preferably, a short-duration of low-medium range ultraviolet radiation is used to crosslink the polymers only a short distance into the polymer, so that the properties of the bulk of the polymer and the bulk of the molecular composite material remain unchanged, but the tough and stable skin formed on the outer surface lends durability and processability to the entire composite material product.
Idaho National Laboratory 03/07/2006
Patent 7,285,362
Safe battery solvents
An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.
Idaho National Laboratory 10/23/2007
Patent 9,206,210
Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids
An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.
Idaho National Laboratory 12/08/2015
Patent 6,544,690
Self-doped molecular composite battery electrolytes
This invention is in solid polymer-based electrolytes for battery applications. It uses molecular composite technology, coupled with unique preparation techniques to render a self-doped, stabilized electrolyte material suitable for inclusion in both primary and secondary batteries. In particular, a salt is incorporated in a nano-composite material formed by the in situ catalyzed condensation of a ceramic precursor in the presence of a solvated polymer material, utilizing a condensation agent comprised of at least one cation amenable to SPE applications. As such, the counterion in the condensation agent used in the formation of the molecular composite is already present as the electrolyte matrix develops. This procedure effectively decouples the cation loading levels required for maximum ionic conductivity from electrolyte physical properties associated with condensation agent loading levels by utilizing the inverse relationship discovered between condensation agent loading and the time domain of the aging step.
Idaho National Laboratory 04/08/2003
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
LIT-PI-471, LIT-PI-571, B-131, BA-342, BA-789PrototypeAvailable09/11/201709/11/2017

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