Silicon-carbon composites

A silicon-carbon composite, comprising:

• a. a carbon scaffold comprising a pore volume, wherein the pore volume comprises greater than 70% microporosity;
• b. a silicon content of 40% to 60% by weight;
• c. 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;
• d. a surface area less than 30 m2/g;
• and
• e. a φ of greater than or equal to 0.1, 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 0.8 V-0.4 V and Regime III is 0.15 V-0 V.