Phosphorus‐Doping‐Induced Surface Vacancies of 3D Na₂Ti₃O₇ Nanowire Arrays Enabling High‐Rate and Long‐Life Sodium Storage

Abstract

Sodium‐ion batteries have attracted interest as an alternative to lithium‐ion batteries because of the abundance and cost effectiveness of sodium. However, suitable anode materials with high‐rate and stable cycling performance are still needed to promote their practical application. Herein, three‐dimensional Na2Ti3O7 nanowire arrays with enriched surface vacancies endowed by phosphorus doping are reported. As anodes for sodium‐ion batteries, they deliver a high specific capacity of 290 mA h g−1at 0.2 C, good rate capability (50 mA h g−1at 20 C), and stable cycling capability (98 % capacity retention over 3100 cycles at 20 C). The superior electrochemical performance is attributed to the synergistic effects of the nanowire arrays and phosphorus doping. The rational structure can provide convenient channels to facilitate ion/electron transport and improve the capacitive contributions. Moreover, the phosphorus‐doping‐induced surface vacancies not only provide more active sites but also improve the intrinsic electrical conductivity of Na2Ti3O7, which will enable electrode materials with excellent sodium storage performance. This work may provide an effective strategy for the synthesis of other anode materials with fast electrochemical reaction kinetics and good sodium storage performance.

Room‐temperature bonding method of bioactive ultrathin glass film on titanium by a dissolution‐polymerization reaction

“…The peak position differences between O 1 s (Ti‐O) and Ti 2 p 3/2 are all about 71.5‐1.7 eV, implying that Ti 4+ compound 31 was formed on the Ti plate surface as the result of the surface reaction. Based on the data of the Ti 2 p 3/2 and O 1 s (Ti‐O) XPS peaks in previous reports, our results show a similarity to that of the peaks in titanate of CaTiO 3 and Na 2 Ti 3 O 7 30,41‐44 . Therefore, the dissolution of the outmost TiO 2 and then reaction with the UGF components in the interface should lead to the formation of an interfacial layer containing amorphous sodium and/or calcium titanates.…”

“…Based on the data of the Ti 2p 3/2 and O 1s (Ti-O) XPS peaks in previous reports, our results show a similarity to that of the peaks in titanate of CaTiO 3 and Na 2 Ti 3 O 7 . 30,[41][42][43][44] Therefore, the dissolution of the outmost TiO 2 and then reaction with the UGF components in the interface should lead to the formation of an interfacial layer containing amorphous sodium and/or calcium titanates. As no Ti 2p peak was found in the XPS spectra of the peeled-off UGF surfaces while the glass components remained on Ti plate after peeling, the formed titanates should has a gradient distribution in the interfacial layer with a higher concentration near the Ti plate side, and the interfacial layer should fracture in the part constructed by the glass components near the UGF side when the UGF is peeled off.…”

Super‐Amphiphilic Na2Ti3O7 Nanofibrous Film Enabling Water–Oil Miscibility

“…The nanofibrous film's XRD pattern corresponds to NTO. [32] In order to further understand the 6 h NTO nanofibrous, Figure 4a-e depicts the results of analyzing the chemical elemental composition of a single nanofibrous by TEM element mapping. The chemical element composition of the nanofibrous was titanium (Ti), oxygen (O), and sodium (Na).…”

Recent Progress on Intercalation‐Based Anode Materials for Low‐Cost Sodium‐Ion Batteries

“…In addition, it has been reported that defect introduction such as with P‐ and lanthanide‐doping introduces surface vacancies into the Na 2 Ti 3 O 7 structure, not only providing more active sites, but also enhancing the intrinsic electrical conductivity of Na 2 Ti 3 O 7 [56,63] . A series of lanthanide (Ln=La, Ce, Nd, Sm, Gd, Er, and Yb) doped microsized Na 2 Ti 3 O 7 anode materials have been synthesized.…”