Ultrasmall TiO₂ Nanoparticles in Situ Growth on Graphene Hybrid as Superior Anode Material for Sodium/Lithium Ion Batteries

Abstract

To inhibit the aggregation of TiO2 nanoparticles and to improve the electrochemical kinetics of TiO2 electrode, a hybrid material of ultrasmall TiO2 nanoparticles in situ grown on rGO nanosheets was obtained by ultraphonic and reflux methods. The size of the TiO2 particles was controlled about 10 nm, and these particles were evenly distributed across the rGO nanosheets. When used for the anode of a sodium ion battery, the electrochemical performance of this hybrid TiO2@rGO was much improved. A capacity of 186.6 mAh g(-1) was obtained after 100 cycles at 0.1 A g(-1), and 112.2 mAh g(-1) could be maintained at 1.0 A g(-1), showing a high capacity and good rate capability. On the basis of the analysis of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the achieved excellent electrochemical performance was mainly attributed to the synergetic effect of well-dispersed ultrasmall TiO2 nanoparticles and conductive graphene network and the improved electrochemical kinetics. The superior electrochemical performance of this hybrid material on lithium storage further confirmed the positive effect of rGO.

Recent Progress in Electrode Materials for Sodium‐Ion Batteries

“…[ 138,269, The storage of Na in carbon materials such as hard carbon, amorphous carbon, defected graphene, and functionalized graphite has been observed to be thermodynamically feasible. [ 325,326,274,276 ] In the early works by Doeff et al, they demonstrated that the extent of Na intercalation in carbon materials varies depending on the carbon structure; NaC 70 , NaC 30 , and NaC 15 were formed for graphite, petroleum coke, and Shawinigan black, respectively. [ 277 ] The inserted Na ions were also reversibly extracted from the carbon materials.…”

“…This work attracted the interest of many researchers in TiO 2 materials; as a result, TiO 2 anodes with various polymorphs (amorphous, anatase, rutile, and bronze) were investigated. [ 325, Kim et al demonstrated that the reversible capacity considerably increases as the discharge cut-off voltage decreases ( Figure 12 a). [ 343 ] When the discharge cut-off voltage was 1.0 V vs Na + /Na, the reversible capacity was limited to ≈8 mA h g −1 .…”

Anode Materials Based on Graphene for Lithium-Ion Batteries

“…Thus, MDC varied just in range of 130 to 250 mA•h•g −1 depending on rate of the charge and discharge for composites of titanium oxide/ graphene [66][67][68][69][70]. A similar composite gave out MDC levels at 247, 238, 225, 210, 187 and 175 mA•h•g −1 at discharge currents of 0.1, 0.2, 0.5, 1, 2.5, and 5C, which was described in [69].…”

Crystalline TiO2@C nanosheet anode with enhanced rate capability for lithium-ion batteries

“…11-13 Nevertheless, one obvious disadvantage of TiO 2 is that it has poor lithium ionic and electrical conductivities, [14][15][16] and this limits the charge/discharge rate. the synthesis and application of unique anatase TiO 2 nanocrystals (NCs) with exposed {001} high-energy facets have been reported by some groups.…”

“…[11][12][13] Nevertheless, one obvious disadvantage of TiO 2 is that it has poor lithium ionic and electrical conductivities, [14][15][16] and this limits the charge/discharge rate. 17,18 It has been widely reported that the cycling stability and intercalation activity depend on the morphology of the TiO 2 anode.…”