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

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 an-odes 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 degrees 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 degrees 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.

Automated summary

The low cost and special structure of biomass materials make them suitable for many energy storage systems. In this study, NiCo2O4 nanowires growing on carbonized ginkgo biloba were developed and used as free-standing anodes for Li-ion batteries. The porous NiCo2O4 nanowires exhibited high capacity and could accommodate volume expansion during cycling. The NiCo2O4/ginkgo biloba anode showed good stability and recoverable rate performance at various current densities, outperforming NiCo2O4/nickel foam and NiCo2O4/carbon cloth. The cost-effective synthesis strategy provides opportunities for other metal oxide/ginkgo biloba-based composites.