Dendrite-Free Lithium Metal Battery by Deformation-Induced Potential Shielding

Abstract

Disclosed are a system and methods for preventing dendrite growth in an electrochemical cell through the use of a protective layer. The electrochemical cell may comprise an anode, a cathode, an electrolyte, and a protective layer, wherein the protective layer is capable of producing a voltage. The voltage produced can selectively shield metal ions from certain regions of the protective layer. This shielding can result in a more uniform flux of metal ions being transferred across the electrode-electrolyte interface in subsequent electrodeposition and electrodissolution processes. As a result, an electrode with such a protective layer can exhibit improved performance and durability, including markedly lower overpotentials and largely improved metal (e.g., lithium) retention.

What is claimed is: 
     
         1 . A method of reducing dendrite growth in an electrochemical cell, the method comprising:
 (a) arranging a protective layer between the anode and the cathode;   (b) generating a voltage in an area of the protective layer; and   (c) shielding metal ions from depositing in the area.   
     
     
         2 . The method of  claim 1 , wherein the voltage generated in the protective layer is produced by at least one of the piezoelectric effect, charge shifting, charge asymmetry, or local charge flow. 
     
     
         3 . The method of  claim 2 , wherein the voltage is generated by the piezoelectric effect. 
     
     
         4 . The method of  claim 3 , wherein the piezoelectric voltage is generated by an anode dendrite contacting the area of the protective layer. 
     
     
         5 . The method of  claim 4 , wherein the voltage is generated by the dendrite pushing on the area of the protective layer in an orthogonal direction. 
     
     
         6 . The method of  claim 4 , wherein the voltage is generated by the dendrite stretching the area of the protective layer in a lateral direction. 
     
     
         7 . The method of  claim 1 , wherein the electrochemical cell is a lithium metal cell, and the metal ions are lithium ions. 
     
     
         8 . The method of  claim 1 , wherein shielding the metal ions includes repelling positively charged ions with the generated voltage, wherein the voltage is positive in the area of the protective layer surrounding any protrusion. 
     
     
         9 . The method of  claim 1 , wherein shielding the metal ions from depositing in the area causes the deposition of lithium ions to increase in other regions of the metal anode, creating a flattened anode surface. 
     
     
         10 . The method of  claim 3 , wherein the method further comprises adjusting or controlling the temperature of the electrochemical cell to induce a change in the piezoelectric properties of the protective layer. 
     
     
         11 . A method for detecting dendrite growth in an electrochemical cell, the method comprising:
 (a) arranging a protective layer between an anode and a cathode of the electrochemical cell; and   (b) detecting a voltage generated in an area of the protective layer by growth of a dendrite on at least one of the anode and the cathode.   
     
     
         12 . The method of  claim 11 , wherein the voltage generated in the protective layer is produced by at least one of the piezoelectric effect, charge shifting, charge asymmetry, or local charge flow. 
     
     
         13 . The method of  claim 11 , wherein the voltage is generated by the piezoelectric effect. 
     
     
         14 . The method of  claim 13 , wherein the voltage is generated by an anode dendrite contacting the area of the protective layer. 
     
     
         15 . The method of  claim 13 , wherein the method further comprises adjusting or controlling the temperature of the electrochemical cell to induce a change in piezoelectric properties of the protective layer. 
     
     
         16 . The method of  claim 13 , wherein the method further comprises monitoring the voltage with a battery management system. 
     
     
         17 . The method of  claim 16 , wherein the battery management system provides information on the growth of the dendrite. 
     
     
         18 . The method of  claim 16 , wherein the battery management system provides a warning that the electrochemical cell is unsafe due to the growth of the dendrite. 
     
     
         19 . The method of  claim 16 , wherein the battery management system provides a warning that the electrochemical cell should be replaced due to the growth of the dendrite. 
     
     
         20 . The method of  claim 16 , wherein the battery management system provides a diagnosis of capability of the electrochemical cell due to the growth of the dendrite.