Multi-shell structures and fabrication methods for battery active materials with expansion properties

Abstract

Battery electrode compositions are provided comprising core-shell composites. Each of the composites may comprise, for example, an active material, a collapsible core, and a shell. The active material may be provided to store and release metal ions during battery operation, whereby the storing and releasing of the metal ions causes a substantial change in volume of the active material. The collapsible core may be disposed in combination with the active material to accommodate the changes in volume. The shell may at least partially encase the active material and the core, the shell being formed from a material that is substantially permeable to the metal ions stored and released by the active material.

1 . A battery electrode composition comprising core-shell composites, each of the composites comprising:
 an active material provided to store and release metal ions during battery operation, whereby the storing and releasing of the metal ions causes a substantial change in volume of the active material;   a collapsible core disposed in combination with the active material to accommodate the changes in volume; and   a shell at least partially encasing the active material and the core, the shell being formed from a material that is substantially permeable to the metal ions stored and released by the active material.   
     
     
         2 . The battery electrode composition of  claim 1 , wherein the collapsible core is formed from a porous material that absorbs the changes in volume via a plurality of open or closed pores. 
     
     
         3 . The battery electrode composition of  claim 2 , wherein the porous material of the core comprises a porous and electrically-conductive carbon material. 
     
     
         4 . The battery electrode composition of  claim 2 , wherein the active material at least partially encases the porous material of the core. 
     
     
         5 . The battery electrode composition of  claim 2 , wherein the active material is interspersed with the porous material of the core. 
     
     
         6 . The battery electrode composition of  claim 2 , wherein the porous material comprises a porous substrate formed of one or more curved linear or planar backbones. 
     
     
         7 . The battery electrode composition of  claim 6 , wherein the porous material further comprises a porous filler interspersed with the porous substrate. 
     
     
         8 . The battery electrode composition of  claim 1 , wherein the collapsible core comprises a central void that is encased by the active material. 
     
     
         9 . The battery electrode composition of  claim 8 , wherein the central void directly contacts the active material. 
     
     
         10 . The battery electrode composition of  claim 1 , wherein the shell comprises a protective coating at least partially encasing the active material and the core to prevent oxidation of the active material. 
     
     
         11 . The battery electrode composition of  claim 1 , wherein the shell comprises a porous coating at least partially encasing the active material and the core, the porous coating having a plurality of open or closed pores to further accommodate changes in volume. 
     
     
         12 . The battery electrode composition of  claim 11 , wherein at least some of the pores in the porous coating are closed pores filled with a first functional filler material. 
     
     
         13 . The battery electrode composition of  claim 12 , wherein at least some other pores in the porous coating are closed pores filled with a second functional filler material. 
     
     
         14 . The battery electrode composition of  claim 11 , wherein at least some of the pores in the porous coating are open pores interpenetrating the porous coating and filled by a functional filler material. 
     
     
         15 . The battery electrode composition of  claim 1 , wherein the shell is a composite material comprising an inner layer and an outer layer. 
     
     
         16 . The battery electrode composition of  claim 15 , wherein the inner layer is one of a protective coating layer or a porous coating layer, and wherein the outer layer is the other of the protective coating layer or the porous coating layer. 
     
     
         17 . The battery electrode composition of  claim 16 , wherein the inner layer is the protective coating layer and the outer layer is the porous coating layer, and wherein the composite material further comprises an additional coating layer at least partially encasing the other layers and formed from a material that is (i) substantially electrically conductive and (ii) substantially impermeable to electrolyte solvent molecules. 
     
     
         18 . The battery electrode composition of  claim 1 , wherein the active material comprises discrete particles disposed around or interspersed with the collapsible core. 
     
     
         19 . The battery electrode composition of  claim 18 , wherein the particles are coated with a protective coating to prevent oxidation of the active material. 
     
     
         20 . The battery electrode composition of  claim 1 , wherein the active material is conformally coated onto the collapsible core.