Highly Stable Iron- and Carbon-Based Electrodes for Li-Ion Batteries: Negative Fading and Fast Charging within 12 Min.

Lithium-ion batteries (LIBs) with high energy density and safety under fast-charging conditions are highly desirable for electric vehicles. However, owing to the growth of Li dendrites, increased temperature at high charging rates, and low specific capacity in commercially available anodes, they cannot meet the market demand. In this study, a facile one-pot electrochemical self-assembly approach has been developed for constructing hybrid electrodes composed of ultrafine Fe O particles on reduced graphene oxide (Fe O @rGO) as anodes for LIBs. The rationally designed Fe O @rGO electrode containing 36 wt % rGO exhibits an increase in specific capacity as cycling progresses, owing to improvements in the active sites, electrochemical kinetics, and catalytic behavior, leading to a high specific capacity of 833 mAh g and outstanding cycling stability over 2000 cycles with a capacity loss of only 0.127 % per cycle at 5 A g , enabling the full charging of batteries within 12 min. Furthermore, the origin of this abnormal improvement in the specific capacity (called negative fading), which exceeds the theoretical capacity, is investigated. This study opens up new possibilities for the commercial feasibility of Fe O @rGO anodes in fast-charging LIBs.