2D Fe 2 O 3 nanosheets with bi-continuous pores inherited from Fe-MOF precursors: an advanced anode material for Li-ion half/full batteries

Two-dimensional (2D) materials are appealing for energy storage devices due to their intriguing chemical and physical properties. Herein, a promising anode material for both half/full cells is well prepared by constructing bi-continuous porous structure in Fe2O3 nanosheets (bp-Fe2O3) through a target construction method. Notably, the obtained bp-Fe2O3 exhibits a unique wrinkled layer structure composed by ultrasmall Fe2O3 nanoparticles, which can well shorten the charge diffusion pathway. Furthermore, the wrinkled layer structure and the presence of pores in the bp-Fe2O3 sample are able to accommodate the volume variation during deep lithiation–delithiation processes, and enable electrolyte easy penetration to the whole electrode, thus significantly improving the electrochemical performance. Benefiting from the favorable electrode framing together with fast lithiation dynamics, the prepared bp-Fe2O3 exhibits considerably better electrochemical performance in half/full cells for lithium ion batteries (LIBs), as well as superior low temperature (low-T) performance. In detail, when cycled at 1.5 A g−1, 2D bp-Fe2O3 electrode displays a reversible capacity up to 818.7 mAh g−1 for 350 cycles. Even at a stern temperature of 0 °C and −25 °C, the as-prepared bp-Fe2O3 still presents a capacity of 840.3 and 635.6 mAh g−1 at 0.5 A g−1, respectively, suggesting the normal operation of LIBs under low temperature condition. More competitively, the full cell fabricated by bp-Fe2O3 anode and LiFePO4 cathode gives excellent electrochemical performance (421.2 mAh g−1 after 80 cycles at 0.1 A g−1) between 0.4 and 3.4 V and high energy density of 247.03 Wh kg−1.