A Bio-Inspired Nanotubular Na2MoO4/TiO2 Composite as a High-Performance Anodic Material for Lithium-Ion Batteries

Abstract

A train of bio-inspired nanotubular Na2MoO4/TiO2 composites were synthesized by using a natural cellulose substance (e.g., commercial ordinary filter paper) as the structural template. The TiO2 gel films were coated on the cellulose nanofiber surfaces via a sol-gel method firstly, followed with the deposition of the poly(diallyldimethylammonium chloride)/Na2MoO4 (PDDA/Na2MoO4) bi-layers several times, through the layer-by-layer self-assembly route, yielding the (PDDA/Na2MoO4)n/TiO2-gel/cellulose composite, which was calcined in air to give various Na2MoO4/TiO2 nanocomposites containing different Na2MoO4 contents (15.4, 24.1, and 41.4%). The resultant nanocomposites all inherited the three-dimensionally porous network structure of the premier cellulose substance, which were formed by hierarchical TiO2 nanotubes anchored with the Na2MoO4 layers. When employed as anodic materials for lithium-ion batteries, those Na2MoO4/TiO2 nanocomposites exhibited promoted electrochemical performances in comparison with the Na2MoO4 powder and pure TiO2 nanotubes, which was resulted from the high capacity of the Na2MoO4 component and the buffering effects of the TiO2 nanotubes. Among all the nanotubular Na2MoO4/TiO2 composites, the one with a Na2MoO4 content of 41.4% showed the best electrochemical properties, such as the cycling stability with a capacity of 180.22 mAh g−1 after 200 charge/discharge cycles (current density: 100 mA g−1) and the optimal rate capability.