Recycling silicon from batteries with silicon-based active materials
Methods of recycling silicon from lithium-ion batteries having silicon-based electrodes are disclosed. Batteries and methods of manufacturing batteries from the recycled silicon are also disclosed. A method of recycling may include discharging each of one or more batteries to below a threshold voltage and disassembling each of the one or more batteries to collect source material from silicon-based electrodes of the one or more batteries. The source material may include silicon from the silicon-based electrodes. The method may further include rinsing the source material in alcohol to obtain a solution and extracting recycled silicon from the solution by heating the silicon for a first period of time and leaching the silicon in an acid for a second period of time. In some methods, the heating occurs before the leaching. In other embodiments, the leaching occurs before the heating.
1 . A method, comprising:
providing a source material that includes active material from one or more battery electrodes;
rinsing the source material in alcohol to place silicon particles from the active material of the one or more electrodes into a solution;
heating the solution and the silicon particles therein for a first period of time, wherein the heating evaporates the solution and leaves behind the silicon particles;
leaching the silicon particles in an acid for a second period of time; and
after the evaporating the solution and the leaching the silicon particles, reclaiming the silicon particles as recycled silicon particles.
2 . The method of claim 1 , wherein the leaching the silicon particles occurs after the heating the solution and the silicon particles.
3 . The method of claim 1 , wherein, prior to the heating the solution and the silicon particles, the leaching the silicon particles comprises subjecting the solution to the acid for the second period of time.
4 . The method of claim 1 , wherein the heating the solution and the silicon particles comprises heating the silicon particles in an oxygen environment at a temperature sufficient to cause oxidation of at least portions of the silicon particles.
5 . The method of claim 1 , wherein the heating the silicon particles comprises heating the silicon particles in ambient air at a temperature sufficient to cause oxidation of at least portions of the silicon particles.
6 . The method of claim 1 , wherein the acid comprises nitric acid.
7 . The method of claim 1 , wherein the leaching the silicon particles comprises leaching the silicon particles in 10 wt % nitric acid for at least 8 hours.
8 . The method of claim 1 , wherein the leaching the silicon particles comprises leaching the silicon particles in 10 wt % nitric acid for at least 12 hours.
9 . The method of claim 1 , wherein the source material comprises at least 25 wt % silicon particles prior to the rinsing.
10 . The method of claim 1 , wherein the source material comprises at least 50 wt % silicon particles prior to the rinsing.
11 . The method of claim 1 , wherein the source material comprises lithium.
12 . The method of claim 1 , wherein the source material comprises copper.
13 . The method of claim 1 , wherein the source material comprises crystalline silicon particles.
14 . The method of claim 1 , wherein the alcohol comprises methanol.
15 . The method of claim 1 , comprising forming an anode with an active material layer comprising the recycled silicon particles.
16 . The method of claim 1 , comprising:
forming a battery comprising an anode with an active material layer; and
wherein the active material layer comprises the recycled silicon particles.
17 . The method of claim 16 , wherein the battery retains at least 80% of its storage capacity after at least 100 cycles at 4 C.
18 . The method of claim 1 , wherein the recycled silicon particles have a capacity of at least 1500 mAh/g.
19 . The method of claim 1 , wherein the recycled silicon particles have a capacity of at least 2000 mAh/g.
20 . The method of claim 1 , wherein the recycled silicon particles have a capacity of at least 2500 mAh/g.
21 . The method of claim 1 , wherein the recycled silicon particles have a capacity of at least 3000 mAh/g.
22 . The method of claim 1 , wherein the recycled silicon particles have a median particle size between 2 μm and 15 μm inclusive.
23 . The method of claim 1 , comprising:
discharging one or more batteries to below a threshold voltage; and
disassembling the one or more batteries to collect the source material from silicon-based electrodes of the one or more batteries.
24 . The method of claim 1 , comprising:
discharging one or more batteries below 2 V; and
disassembling the one or more batteries to collect the source material from silicon-based electrodes of the one or more batteries.
25 . The method of claim 1 , wherein the heating the solution and the silicon particles comprises subjecting the solution and the silicon particles to a temperature of 300-700° C.