High-Performance flexible Quasi-Solid-State aqueous Nickel-Iron battery enabled by MOF-Derived N-Doped carbon hollow nanowall arrays

The development of portable, flexible and wearable electronic devices has accelerated ever-growing demand for high-performance power sources with high specific energy/power density, high-level safety, low cost, and highly flexible features. Herein, a flexible quasi-solid-state aqueous nickel-iron (QSSA Ni-Fe) battery with high energy and power densities is rationally developed using ultrathin Ni(OH)(2) nanoflakes and porous alpha-Fe2O3 nanorods conformally deposited on vertically aligned MOF-derived N-doped carbon hollow nanowalls supported by carbon textiles (NC/CTs) as the cathode (Ni(OH)(2)@NC/CTs) and anode (alpha-Fe2O3@NC/CTs), respectively. The obtained flexible QSSA Ni-Fe battery delivers optimal electrochemical performance, including high energy density (155.4 Wh Kg 1), high power density (14.0 KW Kg(-1)) and excellent cycling stability (similar to 86.1 % retention after 10,000 cycles). Impressively, the flexible QSSA Ni-Fe battery delivers stable electrochemical performance even under different bending conditions. The excellent electrochemical properties may be attributed to the following reasons: (i) The ultrathin Ni(OH)(2) nanoflakes and porous alpha-Fe2O3 nanorods deposited on 2D hollow NC arrays possess a high porosity and large specific surface area; (ii) The 2D hollow NC arrays on flexible CTs not only increase the electrical conductivity, but also function as a scaffold to hold the active materials (such as Ni(OH) 2 or alpha-Fe2O3) and thus maintain the structural integrity of the composites. This work provides a novel approach to design and develop QSSA batteries with satisfactory electrochemical properties and excellent flexibility, and have greater potential for future flexible and wearable electronic devices.

Automated summary

In this research, a flexible quasi-solid-state aqueous nickel-iron battery with high energy density, high power density, and excellent cycling stability is developed using ultrathin Ni(OH)2 nanoflakes and porous alpha-Fe2O3 nanorods as the cathode and anode, respectively. The battery exhibits stable electrochemical performance even under different bending conditions. The ultrathin nanoflakes and porous nanorods deposited on 2D hollow carbon arrays contribute to the excellent electrochemical properties. This work provides a novel approach to design and develop QSSA batteries for future flexible and wearable electronic devices.