Fe3O4–pyrolytic graphite oxide composite as an anode material for lithium secondary batteries

Fe3O4–pyrolytic graphite oxide (Fe3O4–PGO) composite has been prepared by solvothermal reaction at 200 °C. The as-prepared Fe3O4–PGO composite displays excellent cycle stability and rate capability with the initial discharge capacity of 1275 mAh g−1 and capacity retention of 81% after 50 cycles compared with pure Fe3O4. The reasons are as follows: (i) in situ synthesized Fe3O4 firmly anchors onto the exfoliated PGO sheets, and the PGO acts as a conductive agent to provide a fast path for electron transportation; and (ii) the interstitial cluster structure of microsphere-type Fe3O4 in Fe3O4–PGO composite facilitates more better percolation of the electrolyte, more efficient accommodation with the strain and stress of volume change upon cycling and faster Li-ion transfer.

► Fe3O4–pyrolytic graphite oxide (Fe3O4–PGO) composite was prepared by solvothermal reaction at 200 °C. ► PGO is a conductor with electronic conductivity higher than 1 S cm−1 when thermal treating at more than 180 °C. ► PGO is directly used as a conductive agent. ► The results demonstrate that PGO obviously improves electrochemical performance of Fe3O4–PGO composite. ► The discharge capacities of Fe3O4–PGO on the initial cycle are 1275 mAh g−1 and 1035 mAh g−1 after 50 cycles at 0.2 C, respectively.