Sintered polymeric binders for Li-ion battery alloy anodes

The cycling performance in Li half cells of Si alloy electrodes with polyvinylidene fluoride or polyimide binders were evaluated after the electrodes were cured at temperatures below and above the binder carbonization temperature. After carbonization, the cycling performance of electrodes using polyvinylidene fluoride binder improved considerably, but still suffered from capacity fade. Electrodes with carbonized polyimide binder had superior performance and showed no capacity fade after 100 cycles. The superior performance of carbonized polyimide electrodes is thought to be related to polyimide's high carbon yield upon heating, resulting in the formation of a uniform carbon coating on alloy surfaces. These results suggest that new high performance binders for alloy electrodes might be derived by the carbonization of polymers with a high carbon yield that lead to the formation of uniform carbon coatings on alloy particles.