Search

The hollow Si nanospheres modified by the mechanically robust titanium dioxide (TiO 2 ) shell and the uniform carbon layer are intentionally designed and successfully prepared as the anode active material of high performance lithium-ion batteries. The effects of the robust TiO 2 shell and the uniform carbon layer on the structure and electrochemical performances for the Si@TiO 2 @C nanospheres are studied in detail by X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction and charge/discharge tests. The results show that the hollow structure of the Si core can spontaneously absorb the huge volume expansion stress, the robust TiO 2 shell is used as a compact fence to promote the expansion towards the interior of the Si cavity instead of the exterior in the processes of charge/discharge, and the uniform carbon layer can effectively enhance the electrical conductivity and further control the integrity and stability of the well-wrapped core-shell-shell framework. Typically, the resultant hollow Si@TiO 2 @C nanospheres exhibit a high initial discharge capacity of 2557.1 mAh g −1 with coulombic efficiency of 86.06% as well as a large recuperative discharge capacity of 1270.3 mAh g −1 after 250 cycles at 1 A g −1 with a mean coulombic efficiency of 99.53%. Therefore, the hollow Si@TiO 2 @C nanospheres prepared by one-step sol-gel coating process show outstanding electrochemical properties and are considered as a prospective candidate to the adhibitions of the anode material for new generation power LIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • An ultralow-potential H 2 Ti 3 O 7 ·xH 2 O anode is first introduced for zinc-ion batteries. • The storage mechanism of H+ and Zn2+ co-insertion is demonstrated on the H 2 Ti 3 O 7 ·xH 2 O anode. • The H 2 Ti 3 O 7 ·xH 2 O anode features excellent electrochemical performance. • The assembled Zn x MnO 2 //H 2 Ti 3 O 7 ·xH 2 O full battery exhibits the high output voltage. Developing the alternative anode materials that can completely resolve the dendrite concern of Zn metal anodes are desirable for reliable aqueous zinc-ion batteries. However, the sub-optimal charging potentials of reported anodes inevitably cause the discounted output voltage and energy density on a zinc-ion full battery. Herein, it is firstly demonstrated that the hydrated titanic acid (H 2 Ti 3 O 7 ·xH 2 O) can be applied as an ultralow-potential anode for the aqueous zinc-ion full battery. The depressed potential (0.2 V vs. Zn2+/Zn) of the H 2 Ti 3 O 7 ·xH 2 O compared to that of reported candidates could significantly enhance the operating voltage level of the zinc-ion full battery. Furthermore, the comprehensive analyses demonstrate that the expanded lattice spacings and interlayer crystal water stimulate Zn2+ along with H+ to jointly insert and extract on the H 2 Ti 3 O 7 ·xH 2 O anode. The low-potential H 2 Ti 3 O 7 ·xH 2 O anode exhibits an impressive cycling performance and coulombic efficiency by virtue of the assistance from interlayer crystal water. The assembled Zn x MnO 2 //H 2 Ti 3 O 7 ·xH 2 O zinc-ion full battery delivers the decent electrochemical performance, especially a high output voltage of over 1 V. This low-potential, high-stable H 2 Ti 3 O 7 ·xH 2 O anode reveals the exceptional potential for aqueous zinc-ion full batteries. [ABSTRACT FROM AUTHOR]