LITHIUM-SILICON BATTERY
Disclosed herein is an improved lithium-silicon battery. The anode of the battery comprises a composite comprising Group14 elements silicon and carbon. This composite comprises silicon in the preferred form for use in the lithium-silicon battery: silicon that is amorphous, nano-sized, and entrained within porous carbon. Compared to batteries found in the prior art, lithium-silicon batteries disclosed herein comprising the composite anode material disclosed herein find superior utility in various applications.
1 . A lithium-silicon battery comprising an anode comprising a silicon-carbon composite, wherein:
a. the carbon comprises a carbon scaffold comprising a pore volume, wherein the pore volume comprises greater than 80% microporosity; and
b. the composite comprises:
i. a silicon content of 30% to 60% by weight;
ii. a Z of less than 10, wherein Z=1.875×[(M1100−M)/M1100]×100%, wherein M1100 is a mass of the silicon-carbon composite at 1100° C. and M is the minimum mass of the silicon-carbon composite between 800° C. and 1100° C. when the silicon-carbon composite is heated under air from about 25° C. to about 1100° C., as determined by thermogravimetric analysis;
iii. a surface area less than 30 m 2 /g; and
iv. a φ of greater than or equal to 0.15, wherein φ=(Max peak height dQ/dV in Regime I)/(Max peak height dQ/dV in Regime III), wherein dQ/dV is measured in a half-cell coin cell, and Regime I is 0.8V-0.4V and Regime III is 0.15V-0V.
2 . The lithium-silicon battery of claim 1 , wherein the carbon scaffold pore volume comprises greater than 90% microporosity.
3 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite comprises a surface area less than 10 m 2 /g.
4 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite comprises a silicon content of 40% to 60% by weight.
5 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite comprises a Z less than 5.
6 . The lithium-silicon battery of claim 1 , wherein the y is greater than or equal to 0.2.
7 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite further comprises a Dv50 ranging from 5 nm to 20 microns.
8 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite further comprises a capacity of greater than 900 mA/g.
9 . The lithium-silicon battery of claim 1 , wherein the silicon-carbon composite further comprises a first cycle efficiency greater than or equal to 80%.
10 . The lithium-silicon battery of claim 1 , wherein the anode comprises a conductive carbon additive.
11 . The lithium-silicon battery of claim 1 , wherein the anode comprises a binder.
12 . The lithium-silicon battery of claim 1 , wherein the anode comprises the silicon-carbon composite at a concentration ranging from 5% to 95% of the dry weight of the anode.
13 . The lithium-silicon battery of claim 1 , wherein a porosity of the anode ranges from 10% to 50%.
14 . The lithium-silicon battery of claim 1 , wherein a capacity ratio between the anode and a cathode in the battery (N/P ratio) is greater than or equal to 1.1.
15 . The lithium-silicon battery of claim 1 , wherein a capacity ratio between the anode and a cathode in the battery (N/P ratio) is less than 1.1.
16 . The lithium-silicon battery of claim 1 , wherein the lithium-silicon battery comprises an electrolyte selected from LiPF 6 , LiClO 4 , LiBOB, LiTFSI, LiFSI, and LiBF4, and combinations thereof at a total concentration ranging from 0.9M to 2M.
17 . The lithium-silicon battery of claim 1 , wherein the lithium-silicon battery comprises an electrolyte selected from ethyl propyl ether (EPE), fluorinated cyclic carbonate (F-AEC), fluorinated linear carbonate (F-EMC), Dimethylacrylamide (DMAA), Succinic anhydride (SA), tris(trimethylsilyl) borate (TTMB), tris(trimethylsilyl) phosphate (TTSP), 1,3-propane sultone (PS), fluorinated ether (F-EPE), fluoroethylene carbonate (FEC), and vinylene carbonate (VC), and combinations thereof at a total concentration ranging from 0.1% to 30%
18 . The lithium-silicon battery of claim 1 , wherein the lithium-silicon battery comprises a lower end of an operating voltage window of less than or equal to 3.0 V.
19 . The lithium-silicon battery of claim 18 , wherein the lower end of the operating voltage window is less than or equal to 2.7 V.
20 . The lithium-silicon battery of claim 18 , wherein the lower end of the operating voltage window is less than or equal to 2.5 V.