Synthesis and superior electrochemical properties of shaggy hollow Zn-doped Fe₂O₃nanospheres for high-performance lithium-ion batteries

Abstract

Hollow Zn-doped Fe 2 O 3 nanospheres were fabricated by a facile solvothermal method followed by postannealing treatment. The as-synthesized hollow nanospheres have a uniform size with a diameter of about 200-500 nm. The growth mechanism of the hollow Zn-doped Fe 2 O 3 nanospheres was proposed based on many contrast experiments. Compared with Fe 2 O 3 without Zn doping, hollow Zn-doped nanospheres showed an improved electrochemical performance in terms of high rate capability and long cycling performance. At current densities of 1 A g −1 and 2 A g −1 , Zn-doped Fe 2 O 3 exhibited an initial capacity of 861.5 and 698.4 mA h g −1 , respectively, and the capacity was maintained at 580 and 470 mA h g −1 after 500 cycles. These excellent electrochemical properties can be attributed to the unique hollow nanostructure, and Zn doping makes the crystal structure more stable during discharge/charge cycles.

Cooperation of Fe 2 O 3 @C and Co 3 O 4 /C subunits enhances the cyclic stability of Fe 2 O 3 @C/Co 3 O 4 electrodes for lithium‐ion batteries

“…The EIS impedance tests, shown in Figure C, indicate that the reaction impedance decreases with the increase in the number of cycles. The R ct values after 30, 45, 60, 90, and 120 cycles are 109, 110, 85, 64, and 42 Ω, respectively, in agreement with previously reported results . This illustrates that the formation of the new phase does not affect the whole reduction/oxidation reaction but only contributed to increase the capacity.…”

“…The R ct values after 30, 45, 60, 90, and 120 cycles are 109, 110, 85, 64, and 42 Ω, respectively, in agreement with previously reported results. [32][33][34] This illustrates that the formation of the new phase does not affect the whole reduction/oxidation reaction but only contributed to increase the capacity.…”

Biomimetic Straw‐Like Bundle Cobalt‐Doped Fe2O3 Electrodes towards Superior Lithium‐Ion Storage

“…In the Fe 2p XPS region (Figure 1d), two primary peaks are located at 710.6 and 724.2 eV,c orresponding to the binding energies of Fe 2p 3/2 and Fe 2p 1/2 ,r espectively, with as pin energy separation of 13.6 eV. [27] Furthermore, two shake-up satellite peaks at 718.5 and 732.4 eV are detected. [39] Figure 1e shows two clear peaks at 780.6 and 796.0 eV,w hich can be ascribed to the Co 2p 3/2 and Co 2p 1/2 ,r espectively,a nd the separation of the 2p doubleti s1 5.6 eV.…”

“…Thus, researchers have studied Fe 2 O 3 composites with other doping metal elements (Zn, [27] Cr, [28] and Co) [29] to improve the intrinsic conductivity.Y ang et al [30] prepared platelets-like Tidoped Fe 2 O 3 through ball-millingw ith post-annealing. The cyclic stability of Fe 2 O 3 is improved by doping Ti 4 + ,g iving the reversible capacity of 454.9 mA h À1 g À1 at 100 mA g À1 after 550 cycles (46.4 %r etention of the initial discharge specific capacity).…”

“…[35] Second, the radius of Co 2 + (0.082 nm) is greater than that of Fe 3 + (0.055 nm) in the crystal, so Fe 3 + is partially substituted for the doped Co 2 + .T hise nlarges the unit cell volume, making the diffusion of Li ions easier. [27,35] Third, the biomimetic straw-like bundlemorphology of SCF can accelerateL ii on diffusion and buffert he huge volumev ariation upon cycling. These merits result in the prominente lectrochemical performance of SCF,i ndicatingt he potentialapplication in LIBs.…”