Low-quality graphite (L-Graphite) is converted directly and efficiently into high-quality iodinated graphene nanoplatelets (HIGnP) through simple ball-milling method. The resultant HIGnP shows distinguished characteristic such as large specific surface area (969 m2/g), low metal impurity (3.2 wt.%), high iodine content (3.28 at.%), high crystallinity and remarkable electrocatalytic activity with higher selectivity, longer-term stability and better tolerance to methanol crossover/CO poisoning effects.