Synergistic effects of flake-like ZnO/SnFe₂O₄/nitrogen-doped carbon composites on structural stability and...

In order to improve the electrochemical performance and relieve volume expansion of pure SnFe₂O₄ anode for lithium-ion batteries (LIBs), we synthesized a novel ZnO/SnFe₂O₄/nitrogen-doped carbon composites (ZSFO/NC) with flake-like polyhedron morphology by using ZIF-8 as a sacrificial template. Remarkably, it exhibited an initial charge/discharge capacities of 1078.3/1507.5 mAh g^-1 with a high initial coulombic efficiency (ICE) of 71.2%, and maintained a steady charge/discharge capacities of 1495.7/1511.8 mAh g^-1 at 0.2 A g^-1 after 300 cycles. The excellent rate performance of 435.6 mAh g^-1 at a higher current density of 10.0 A g^-1 and superior reversible capacity of 532.3/536.2 mAh g^-1 after 500 cycles at 2.0 A g^-1 were obtained. It revealed that the nitrogen-doped carbon matrix and peculiar structure of ZSFO/NC not only effectively buffered large volume expansion upon (de)lithiation through the synergistic interface action between ZnO, SnFe₂O₄ and NC, but also improved capacity of the composite by large contribution of surface pseudo-capacitance. The excellent charge-discharge performance showed that ZSFO/NC composite has a great potential for LIBs due to the synergistic effect of the multi-components.