Free-standing nanowires growing on ginkgo biloba as high areal capacity Li-ion battery anode at high and low temperatures

Abstract

The low cost and special structure of biomass materials enable them to be applicable for many energy-storage systems. Here, we develop NiCo2O4 nanowires growing on carbonized ginkgo biloba to form free-standing anodes of Li-ion battery. The porous NiCo2O4 nanowires have a high capacity, and they are able to accommodate the expansion of volume in cycling. Low surface reaction barrier of the NiCo2O4/ginkgo biloba anode is confirmed by galvanostatic intermittent titration technique analysis. The NiCo2O4/ginkgo biloba anode displays recoverable rate-performance and good stability when cycling at different current densities, which remains 2.6 mAh cm−2 after 350 cycles at room temperature. The Coulombic efficiency is about 99 % under −10 °C at 1 mA cm−2, and the capacity remains 1.28 mAh cm−2 after cycling 200 times. Capacity keeps 1.83 mA cm−2 under 45 °C, exhibiting a good Li-storage performance. The NiCo2O4/ginkgo biloba anode displays a better cycling performance than NiCo2O4/nickel foam and NiCo2O4/carbon cloth. The cost-effective synthesis strategy provides extensible applications for metal oxide/ginkgo biloba-based composites. Growing other binary metal oxides on the carbonized ginkgo biloba is also achievable such as ZnCo2O4, indicating the developed composite system is promising for preparing other free-standing energy-storage composites.