Partial Nitridation-Induced Electrochemistry Enhancement of Ternary Oxide Nanosheets for Fiber Energy Storage Device

Fiber-based power sources are receiving interest in terms of application in wearable electronic devices. Herein, fiber-shaped all-solid-state asymmetric energy storage devices are fabricated based on a partially nitridized NiCo2O4 hybrid nanostructures on graphite fibers (GFs). The surface nitridation leads to a 3D pearled-veil network structure, in which Ni-Co-N nanospheres are mounted on NiCo2O4 nanosheets' electrode. It is demonstrated that the hybrid materials are more potent than the pure NiCo2O4 in energy storage applications due to a cooperative effect between the constituents. The Ni-Co-N segments augment the pristine oxide nanosheets by enhancing both capacity and rate performance (a specific capacity of 384.75 mAh g(-1) at 4 A g(-1), and a capacity retention of 86.5% as the current is increased to 20 A g(-1)). The whole material system has a metallic conductivity that renders high-rate charge and discharge, and an extremely soft feature, so that it can wrap around arbitrary-shaped holders. All-solid-state asymmetric device is fabricated using Ni-Co-N/NiCo2O4/GFs and carbon nanotubes/GFs as the electrodes. The flexible device delivers outstanding performance compared to most oxide-based full devices. These structured hybrid materials may find applications in miniaturized foldable energy devices.