Abstract
Binary transition-metal oxides (BTMOs) with hierarchical micro-nano-structures have attracted great interest as potential anode materials for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower-like CoFe2O4(cl-CoFe2O4) via a facile room-temperature co-precipitation method followed by post-synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro-nano-structure can promote fast ion transport and stable electrode-electrolyte interfaces. As a result, the cl-CoFe(2)O(4)can deliver a high specific capacity (1019.9 mAh g(-1)at 0.1 A g(-1)), excellent rate capability (626.0 mAh g(-1)at 5 A g(-1)), and good cyclability (675.4 mAh g(-1)at 4 A g(-1)for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 degrees C and -25 degrees C, the cl-CoFe(2)O(4)anode can deliver high capacities of 907.5 and 664.5 mAh g(-1)at 100 mA g(-1), respectively, indicating its wide operating temperature. More importantly, the full-cell assembled with a commercial LiFePO(4)cathode exhibits a high rate performance (214.2 mAh g(-1)at 5000 mA g(-1)) and an impressive cycling performance (612.7 mAh g(-1)over 140 cycles at 300 mA g(-1)) in the voltage range of 0.5-3.6 V. Kinetic analysis reveals that the electrochemical performance of cl-CoFe(2)O(4)is dominated by pseudocapacitive behavior, leading to fast Li(+)insertion/extraction and good cycling life.