Activated carbon/reduced graphene oxide wrapped LiFePO4 cathode for Li-ion batteries with ultrahigh capacities and high specific energy density

Abstract

We report a commercially LiFePO4 (LFP) cathode modified by introducing activated carbon/reduced graphene oxide noted as AC/rGO, along the slurry preparation process. The prepared cathode could accomplish an ultra-high-capacity long cycling stability and high specific energy density due to the formation of a stable interface between the cathode and electrolyte, abundant pathways for lithium diffusion, and fast electron migration during charge and discharge processes assisted by AC/rGO wrapped on the LFP cathode. AC/rGO effectively protected LiFePO4 against current attack. AC/rGO with lithium iron phosphate noted as (AC/rGO@LFP) with 1.315 wt% AC/rGO showed an ultra-high initial discharge capacity of 212 mAh g−1 at 0.1C and yielded a high specific energy density of 636 W h kg−1 at a power density of 75.26 W kg−1 with 90 mAh g−1 of capacity at 5C after 2000 cycles. Moreover, a capacity of 109.2 mAh g−1 was achieved in full cells using AC/rGO@LFP with 1.315 wt% AC/rGO as cathode and hard-carbon (H-C) as anode at 3C after 200 cycles. This study marks, for the first time, the introduction of AC/rGO into the preparation of LFP cathode material of Li-ion batteries toward outstanding capacity and cycling stability. Such a scalable and simple approach may be applicable to other cathode composite materials to boost their electrochemical behavior.