Sulphonated coal tar pitch as a carbon source to develop the storage capacity of Fe2O3@C materials

Utilizing metal oxides as substitutes for carbon anodes is imperative in advancing LIBs . Recently, the researchers regarding to the Fe 2 O 3 have become very popular owing to its advantages such as a high theoretical capacity (1007 mAh g −1 ), cost-effectiveness and sustainability. In our present studies, the Fe 2 O 3 @SCTPC (Fe 2 O 3 nanosphere coated by carbons which are obtained by the carbonizations using the sulphonated coal tar pitches) materials are firstly and successfully fabricated by a one-step hydrothermal method using the Fe(NO 3 ) 3 ·9 H 2 O and sulphonated coal tar pitches (SCTPs). An intriguing observation is that the nanosphere Fe 2 O 3 is encapsulated by carbons with a core-shell structure. This specific core-shell structure effectively mitigates the volume expansion of Fe 2 O 3 , and exhibits a notable enhancement in conductivity. Thanks to this unique structure, the Fe 2 O 3 @SCTPC electrode has a maximum capacity of 1106.74 mAh g −1 after 100 cycles at a current density of 0.1 A g −1 and a high reversible specific capacity of 373.5 mAh g −1 after 500 cycles at a current density of 2 A g −1 , when it is used as an anode material for Li-ion battery. These results suggest that adjusting the structures of carbons is crucial to develop the potential storage capacity of the covered Fe 2 O 3 . • Sulphonated coal tar pitch is a useful carbon source to enhance the storage capacity of Fe 2 O 3 . • The Fe 2 O 3 in fabricated Fe 2 O 3 @C materials exhibits the intrinsic storage capacity of Fe 2 O 3 . • The core-shell structures of carbons develop the intrinsic storage capacity of Fe 2 O 3 .