Lithium–sulfur (Li–S) batteries are candidates for next-generation energy storage systems because of their low cost, high theoretical specific capacity and safety. However, the serious lithium polysulfide (LiPS) shuttle effect leads to a loss of reactive active substances and reduction of coulombic efficiency. In the current work, iron oxide (IO-700)—prepared by calcining a mixture of carbon spheres and ferric nitrate under an air atmosphere at 700 °C—was designed as a separator modifier to effectively adsorb LiPSs and accelerate the kinetics of the transformation of the intermediates, thereby inhibiting the shuttle effect. Li–S batteries including IO-700 showed long-term stability for 1000 cycles at 1C, with a capacity decay rate per cycle of only 0.0487%. A theoretical calculation indicated that, due to strongly polar active sites, Fe₂O₃ adsorbed LiPSs effectively to suppress the shuttle effect. This work has highlighted the importance for Li–S batteries of strongly polar active sites for anchoring LiPSs to inhibit the shuttle effect.

Ultrahigh depth range spectral domain optical coherence tomography (SDOCT) can be realized based on the orthogonal dispersive spectrometer consisted by a high spectral resolution virtually-imaged phased array (VIPA) and a low spectral resolution grating. However, two critical issues result in the challenge of obtaining desirable one-dimensional (1-D) spectra from the recorded two-dimensional (2-D) orthogonal spectra for high-quality OD-SDOCT imaging. One is the wavenumber mapping errors and the other is the periodic intensity modulations. The paper proposes a method for desirable reconstruction of 1-D spectra from the recorded 2-D orthogonal spectra. A sample etalon with identical parameters to the dispersive VIPA is used to determine the free spectrum range (FSR) of the VIPA, and spectral phases from two reflecting mirrors are further applied for broadband wavenumber calibration. The cascading of column spectra are performed from interval of four lines of column spectra, and four records of cascaded 1-D spectra are obtained and then averaged to alleviate the periodic intensity modulations. Broadband 1-D spectra are thus reconstructed with an ultrahigh spectral resolution. To demonstrate the feasibility of the proposed method, three typical samples are imaged by the OD-SDOCT system.