Controlled nanostructure of a graphene nanosheet‐TiO 2 composite fabricated via mediation of organic ligands for high‐performance Li storage applications

Summary A graphene nanosheet‐TiO 2 nanoparticle composite (L‐GNS‐TiO 2 ) was prepared for an application as a high‐performance lithium storage device (or lithium‐ion battery anode). The composite features a well‐defined hybrid structure of GNS and homogeneously distributed anatase TiO 2 nanoparticles due to nanoparticulation and modification by organic ligands (polyacrylic acid, tartaric acid, and diethylene glycol). Despite its low overall carbon content (~8.4%), the L‐GNS‐TiO 2 composite‐based anode exhibited highly reversible lithiation/delithiation (Coulombic efficiency >97%), excellent capacity retention (206 (92%) and 331 (147%) mAh g −1 after 50 and 450 cycles, respectively, at 0.15 A g −1 ) and decent rate capability (164 mAh g −1 at 0.75 A g −1 ). In addition, the stable morphology/structure of the composite after lengthy cycle tests reflected its mechanical robustness and electrochemical reversibility. The excellent performance of L‐GNS‐TiO 2 was attributed to the enhanced electronic conductivity, retained charge storage sites, and a short Li + diffusion pathway enabled by the unique composite structure constructed through optimized ligand mediation. Highlights A graphene nanosheet‐TiO 2 nanoparticle composite (L‐GNS‐TiO 2 ) was prepared for Li storage applications. L‐GNS‐TiO 2 possesses a structure containing uniformly distributed anatase TiO 2 nanoparticles on GNS due to optimized mediation and nanoparticulation by organic ligands. L‐GNS‐TiO 2 exhibits enhanced conductivity, retains charge storage sites, and facilitates Li + transport/charge transfer. Excellent cycle stability (>100% capacity retention, 331 mAh g −1 ) and Coulombic efficiency (>99%) were realized after 450 cycles at 0.15 A g −1 . Decent rate capability was achieved with a high capacity (164 mAh g −1 ) at 0.75 A g −1 .