Synthesis and anode properties of corundum-type structured (Fe2O3)1-x(Al2O3)x solid solutions in the whole compositional range

We have successfully synthesized corundum-type structured solid solutions of (Fe2O3)1-x(Al2O3)x in the whole compositional range (0 ≤ x ≤ 1) by means of mechanochemical synthesis route starting from γ-Fe2O3 and γ-Al2O3 mixture. The lattice parameters of the obtained solid solution coincide with the calculated values assuming Vegard's rule based on the JCPDS card data of α-Fe2O3 (33-664) and α-Al2O3 (46-1212), indicating that the composition of the obtained solid solution is essentially equivalent to the initial Fe2O3/Al2O3 ratio in the starting materials. The test cells using the obtained solid solution as the active material exhibited good cycle performances. Especially in the compositional range in 0.33 ≤ x ≤ 0.45, after a gradual decrease in charge-discharge capacity down to ~ 300 mAhg− 1 for around 100 cycles, the capacity recovers again. Even for x = 0.95, the capacity retains at least 100 mAhg− 1 after 260th cycles, which is larger than the estimated from the Fe2O3 amount.