Microwave-assisted synthesis of biochar‑carbon-nanotube-NiO composite as high-performance anode materials for lithium-ion batteries

We report the synthesis of biochar-CNT-NiO composite and its application as anode material in lithium-ion batteries (LIBs). The scanning electron microscope (SEM) analysis results displayed that the NiO particles were exposed on the surface of CNTs. HRTEM results showed a more uniform distribution of NiO particles on the biochar-CNT-NiO compared to that of biochar-NiO. The electrochemical performance of the biochar-CNT-NiO indicated that composite nanostructure was able to deliver an excellent reversible capacity for LIB. The capacity of biochar-CNT-NiO (674.6 mAh/g) was significantly higher than biochar-NiO without CNTs (368.4 mAh/g) and Char-CNT-Ni (140.9 mAh/g) after 100 cycles. The biochar-CNT-NiO composite exhibited a remarkable discharge rate performance. This outstanding performance was caused by the presence of CNTs on the biochar-CNT-NiO, which mitigates the volume change of NiO during cycles and speeded up electron transfer.