The controlled synthesis and improved electrochemical cyclability of Mn-doped α-Fe2O3 hollow porous quadrangular prisms as lithium-ion battery anodes

A two-step process of initial oxalate co-precipitation and subsequent thermal decomposition facilitates the formation of hydrated oxalate precursors with hollow quadrangular prism shapes, and then confers a porous nature for the prismatic shells of synthetic hematite (alpha-Fe2O3) and its Mn-doped derivative. When applied as lithium-ion battery anodes, Mn-doped alpha-Fe2O3 exhibits an improved electrochemical performance compared with undoped alpha-Fe2O3. At a current density of 200 mA g(-1), the pure alpha-Fe2O3 electrode gives an initial discharge capacity of similar to 1280 mA h g(-1) with a low retention ratio of 13.9% (i.e., capacity similar to 178 mA h g(-1)) over 80 cycles, while the Mn-doped product, rhombohedral Fe1.7Mn0.3O3, delivers a relatively low initial value of similar to 1190 mA h g(-1) and retains an 80th cycle reversible capacity of similar to 1000 mA h g(-1) (i. e., retention ratio similar to 84.0%). These, together with the better high-rate capability and the lower charge-transfer resistance of the Mn-doped alpha-Fe2O3 anode, simultaneously demonstrate a successful mass production of hollow porous configurations and an effective doping with elemental Mn for potential application.