Method for in situ growth of axial geometry carbon structures in electrodes

A method of forming a plurality of axial geometry carbon structures in situ in an electrode for an electrochemical cell that cycles lithium ions, the method comprising:

• mixing a plurality of electroactive particles that undergo volumetric expansion within the electrode as the electrochemical cell cycles lithium ions, a polymer precursor comprising polyimide, polyacrylonitrile, poly(methyl methacrylate), polyvinylidene fluoride, sodium alginate, lithium alginate, and combinations thereof, and a plurality of catalytic nanoparticles comprising a metal selected from the group consisting of:
• iron, nickel, cobalt, alloys, and combinations thereof to form a substantially homogeneous slurry;
• applying the slurry to a substrate;
• and
• heating the slurry in an environment having a temperature of less than or equal to about 895° C. to pyrolyze the polymer precursor so that the plurality of catalytic nanoparticles facilitates precipitation of carbon to grow a plurality of axial geometry carbon structures, wherein after the heating, the electrode includes an electrically conductive carbonaceous porous network comprising the plurality of electroactive particles and the plurality of axial geometry carbon structures.