Compositions and uses thereof

1. A silicon-carbon particulate composite suitable for use as active material in a negative electrode of a Li-ion battery, comprising:

(i) a microporosity of from about 5.0% to about 25.0%;

(ii) a BJH average pore width of less than about 250 Å; and

(iii) a BJH volume of pores of from about 0.05 cm 3 /g to about 0.25 cm 3 /g;

wherein the carbon comprises natural graphite, synthetic graphite, or a mixture of natural and synthetic graphite.

2. The silicon-carbon particulate composite according to claim 1 , comprising one or more of:

(i) a BET SSA of equal to or lower than about 400 m 2 /g;

(ii) an average particle size of from about 50-2000 Å;

(iii) a microporosity of from about 5% to about 20%;

(iv) a BJH average pore width of from about 75 Å to about 150 Å; and

(v) a BJH volume of pores of at least about 0.50 cm 3 /g.

3. The silicon-carbon particulate composition according to claim 1 , comprising one or more of:

(i) a microporosity of from about 5% to about 15%;

(ii) a BJH average pore width of from about 100 Å to about 180 Å;

(iii) a BJH volume of pores of at least about 0.10 cm 3 /g;

(iv) a BET specific surface area (SSA) of from about 10 m 2 /g to about 100 m 2 /g; and

(v) an average particle size of from about 250 Å to about 1000 Å.

4. The silicon-carbon particulate composite according to claim 1 , wherein the silicon-carbon particulate composite is a co-milled composite.

5. The silicon-carbon particulate composite of claim 1 , wherein the natural or synthetic graphite is exfoliated graphite or expanded graphite.

6. A negative electrode comprising a silicon-carbon particulate composite according to claim 1 .

7. A device comprising the negative electrode according to claim 6 , wherein the device is an electric vehicle or a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

8. A device comprising the negative electrode according to claim 6 , wherein the device comprises an energy storage cell or an energy storage and conversion system.

9. The device according to claim 8 , wherein the energy storage and conversion system comprises a capacitor or a fuel cell.

10. A Li-ion battery comprising an electrode according to claim 6 , wherein silicon pulverization does not occur during 1 st cycle lithium intercalation and de-intercalation and/or wherein electrochemical capacity is maintained after 100 cycles.

11. A negative electrode of a Li-ion battery comprising a silicon-carbon particulate composite according to claim 1 , wherein:

(i) the electrode exhibits reduced silicon pulverization during 1st cycle Li intercalation or de-intercalation,

(ii) the electrode maintains electrochemical capacity after 100 cycles; and

(iii) Li is electrochemically extracted from an amorphous lithium silicon phase and in the substantial absence of two crystalline phases containing crystalline Si silicon metal and crystalline Li 15 S 4 alloy.

12. A negative electrode of a Li-ion battery comprising a silicon-carbon particulate composite according to claim 1 , wherein the electrode exhibits improved cycling stability of the Li-ion battery compared to a Li-ion battery that comprises an active material which is a mixture of silicon particulate and carbonaceous particulate which is not a composite and/or does not have a nanostructure which inhibits or prevents silicon pulverization during cycling, and/or which is not prepared by co-milling and/or does not have a nanostructure which maintains electrochemical after 100 cycles.

13. A precursor composition for a negative electrode of a Li-ion battery, the precursor composition comprising a silicon-carbon particulate composite according to claim 1 , and a further carbonaceous particulate, wherein the further carbonaceous particulate comprises at least two different types of carbonaceous particulate.

14. The precursor composition according to claim 13 , wherein:

(i) the BET SSA of the precursor composition is lower than the BET SSA of the silicon-carbon particulate composite;

(ii) the BET SSA of the precursor composition is equal to or lower than about 10 m 2 /g; and

(iii) the amounts of silicon-carbon particulate composite and further carbonaceous particulate are such that the precursor composition comprises from about 1 wt. % to about 90 wt. % silicon, based on the total weight of the precursor composition.