Metal sulfide electrodes and energy storage devices thereof

Abstract

The present invention generally relates to energy storage devices, and to metal sulfide energy storage devices in particular. Some aspects of the invention relate to energy storage devices comprising at least one flowable electrode, wherein the flowable electrode comprises an electroactive metal sulfide material suspended and/or dissolved in a carrier fluid. In some embodiments, the flowable electrode further comprises a plurality of electronically conductive particles suspended and/or dissolved in the carrier fluid, wherein the electronically conductive particles form a percolating conductive network. An energy storage device comprising a flowable electrode comprising a metal sulfide electroactive material and a percolating conductive network may advantageously exhibit, upon reversible cycling, higher energy densities and specific capacities than conventional energy storage devices.

1 . (canceled) 
     
     
         2 . An electrode, comprising:
 an electroactive material comprising sulfur or a metal sulfide; and   a percolating electronically conductive network comprising a plurality of electronically conductive particles,   wherein the electrode is substantially fluid prior to first use.   
     
     
         3 . The electrode of  claim 2 , further comprising a fluid. 
     
     
         4 . The electrode of  claim 3 , wherein the sulfur or metal sulfide is suspended and/or dissolved in the fluid. 
     
     
         5 . The electrode of  claim 2 , wherein the electronically conductive particles are suspended in the fluid. 
     
     
         6 . An energy storage device, comprising:
 a first electrode comprising an electrode composition comprising a first electroactive material comprising sulfur, wherein the first electroactive material is suspended and/or dissolved in a fluid, wherein the concentration of sulfur is at least about 2 M; and   a second electrode in electrochemical communication with the first electrode, wherein the second electrode comprises a second electroactive material comprising an electroactive metal or metal alloy comprising a non-sulfur element.   
     
     
         7 . The energy storage device of  claim 6 , wherein at least one of the electrodes of the energy storage device is substantially fluid prior to first use. 
     
     
         8 . The energy storage device of  claim 7 , wherein the fluid comprises TEGDME, DME, diglyme, triglyme, DOL, THF, methyl-TFH, GBL, and/or mixtures thereof. 
     
     
         9 . The energy storage device of  claim 6 , further comprising a layer adjacent the second electrode of the energy storage device. 
     
     
         10 . The energy storage device of  claim 9 , wherein the layer comprises LiNO 3 . 
     
     
         11 . The energy storage device of  claim 9 , wherein the layer comprises a ceramic and/or a polymer. 
     
     
         12 . The energy storage device of  claim 6 , wherein the second electrode comprises lithium metal. 
     
     
         13 . The energy storage device of  claim 6 , further comprising an ionically conductive membrane separating the first and second electrodes. 
     
     
         14 . The energy storage device of  claim 6 , further comprising a metal salt. 
     
     
         15 . The energy storage device of  claim 14 , wherein the metal salt comprises LiTFSI, lithium triflate, sodium triflate, lithium perchlorate, sodium perchlorate, lithium tetrafluoroborate, and/or sodium tetrafluoroborate. 
     
     
         16 . The energy storage device of  claim 6 , wherein the electronically conductive particles comprise carbon black particles. 
     
     
         17 . The energy storage device of  claim 6 , wherein the concentration of the first electroactive material in the fluid is at least about 1 M. 
     
     
         18 . The energy storage device of  claim 6 , wherein the viscosity of the electrode composition is less than about 100 Pa-s at a shear rate of about 100 s −1 . 
     
     
         19 . The energy storage device of  claim 6 , wherein the yield stress of the electrode composition is less than about 1000 Pa. 
     
     
         20 . The energy storage device of  claim 6 , wherein the electronic conductivity of the first electrode is at least about 0.1 mS/cm. 
     
     
         21 . A method of operating an energy storage device, comprising:
 reversibly cycling an energy storage device containing a flowable electrode such that a metal sulfide is precipitated and subsequently dissolved in the flowable electrode during the cycling.   
     
     
         22 . The method of  claim 21 , wherein the precipitated and dissolved metal sulfide comprises Li 2 S. 
     
     
         23 . The method of  claim 21 , wherein the reversible cycling occurs over a voltage range of from about 0.45 V to about 2.7 V. 
     
     
         24 . The method of  claim 21 , wherein the flowable electrode of the energy storage device is in motion during at least a portion of the cycling. 
     
     
         25 . The method of  claim 21 , wherein reversible cycling of the energy storage device comprises:
 transporting the flowable electrode through an electrode compartment;   inhibiting the flow of the flowable electrode;   at least partially charging or discharging a portion of the flowable electrode; and   transporting the flowable electrode out of the electrode compartment.   
     
     
         26 . The method of  claim 21 , wherein the flowable electrode comprises an electroactive material comprising sulfur or a metal sulfide suspended and/or dissolved in a fluid, and a percolating electronically conductive network comprising electronically conductive particles suspended in the fluid.