Figure 6

Electrochemical performance of best-performing porous CaFe2O4 anode (ϕ = 1.325, 900 °C calcination): (a) galvanostatic charge–discharge curves of 1st, 2nd, and 20th cycles at a current density of 109 mA-g-1; (b) rate performance in specific capacity; (c) rate performance in specific energy; (d) cycling stability at 1088 mA-g-1 up to additional 500 cycles after initial 20 cycle rate performance. Expectedly large initial efficiencies are omitted for clarity (Figure S2).