LiFePO₄ Anchored on Pristine Graphene for Ultrafast Lithium Battery

Defects make a difference in the performance of graphene or other carbonaceous materials when used as conductive additives in electrodes. Reduced graphene oxide (rGO) has been widely used in lithium iron phosphate cathode (LiFePO4) to promote electron transport and improve lithium storage. Though the defects in rGO or GO induce strong coupling between LiFePO4 nanoparticles and conductive sheets, they inevitably impair the in-plane carrier mobility and thus the conductivity throughout the electrode. In this work, LiFePO4 was robustly anchored on pristine graphene with the assistance of branched polyethylenimine. The pristine graphene used here features with high crystallinity and anti-restacking merit. The resulting composite electrodes reveal excellent rate performance: a specific capacity of 143 mAh g–1 at 10 C (1.7 A g–1) and 137 mAh g–1 at 20 C (3.4 A g–1).