COMPOSITE ANODE MATERIAL INCLUDING SURFACE-STABILIZED ACTIVE MATERIAL PARTICLES AND METHODS OF MAKING SAME
Composite anode materials and methods of making same, the anode materials including capsules including graphene, reduced graphene oxide, graphene oxide, or a combination thereof, and particles of an active material disposed inside of the capsules. The particles may each include a core and a buffer layer surrounding the core. The core may include crystalline silicon, and the buffer layer may include a silicon oxide, a lithium silicate, carbon, or a combination thereof.
1 . A composite electrode material comprising active material particles, each active material particle comprising:
an electrochemically active core; and
a buffer layer that surrounds the core and comprises Li 2 Si 2 O 5 , Li 2 SiO 3 , Li 4 SiO 4 , or combinations thereof.
2 . The electrode material of claim 1 , wherein the core comprises crystalline silicon.
3 . The electrode material of claim 1 , further comprising a carbon-based material.
4 . The electrode material of claim 1 , wherein the buffer layer further comprises a layer of carbon.
5 . The electrode material of claim 1 , wherein the buffer layer comprises a matrix.
6 . The electrode material of claim 1 , wherein the active material particles have an average particle size that ranges from about 30 nm to about 500 nm.
7 . The electrode material of claim 1 , wherein the buffer layer has an average thickness that ranges from about 1 nm to about 50 nm.
8 . The electrode material of claim 1 , wherein the buffer layer has an average thickness that ranges from about 5 nm to about 10 nm.
9 . The electrode material of claim 1 , wherein the buffer layer comprises the Li 2 Si 2 O 5 .
10 . The electrode material of claim 1 , wherein the buffer layer comprises the Li 2 SiO 3 .
11 . The electrode material of claim 1 , wherein the buffer layer comprises the Li 4 SiO 4 .
12 . The electrode material of claim 1 , wherein the buffer layer comprises the Li 2 Si 2 O 5 , the Li 2 SiO 3 , and the Li 4 SiO 4 .
13 . A method of forming an anode active material, the method comprising:
heating a dry mixture comprising silicon oxide particles and a lithium salt to form active material particles, each active material particle comprising:
an electrochemically active core; and
a buffer layer that surrounds the core and comprises Li 2 Si 2 O 5 , Li 2 SiO 3 , Li 4 SiO 4 , or combinations thereof.
14 . The method of claim 13 , wherein the buffer layer further comprises a carbon-based material.
15 . The method of claim 13 , wherein the buffer layer further comprises a layer of carbon.
16 . The method of claim 13 , wherein the buffer layer comprises the Li 2 Si 2 O 5 .
17 . The method of claim 13 , wherein the buffer layer comprises the Li 2 SiO 3 .
18 . The method of claim 13 , wherein the buffer layer comprises the Li 4 SiO 4 .
19 . The method of claim 13 , wherein the buffer layer comprises the Li 2 Si 2 O 5 , the Li 2 SiO 3 , and the Li 4 SiO 4 .