3D pollen-scaffolded NiSe composite encapsulated by MOF-derived carbon shell as a high-low temperature anode for Na-ion storage

Abstract

As a novel sodium ion battery anode material, 3D pollen-scaffolded NiSe composite encapsulated by metal-organic framework-derived (MOF-derived) carbon shell is synthesized, denoted as P–NiSe@C. The results depict that well-crystallized NiSe particles were in-situ grown on 3D pollen framework, preventing the particles aggregation effectively. Meanwhile, the pyrolytic MOF-derived shell from 2-methylimidazole further strengthens the adhesion between NiSe particles and pollen skeleton, which would enhance the structural stability and mitigate the volumetric changes during sodium intercalation/deintercalation. Compared with the inferior sodium storage capability of raw NiSe, the P–NiSe@C electrode delivers a sustainably reversible capacity of 598.2 mAh g−1 (200 mA g−1 after 100 cycles) and excellent rate performance of 488.9 mAh g−1 even at a large current density of 2000 mA g−1. The P–NiSe@C electrode also has an impressive high-low temperature adaptability with durable and controllable capacities of 343.8–792.6 mAh g−1 from −5 to 70 °C. © 2019 Elsevier Ltd