Layered Double Hydroxide Quantum Dots for Use in a Bifunctional Separator of Lithium–Sulfur Batteries

Abstract

Functional separators, which are chemically modified and coated with nanostructured materials, are considered an effective and economical approach to suppressing the shuttle effect of lithium polysulfide (LiPS) and promoting the conversion kinetics of sulfur cathodes. Herein, we report cobalt−aluminum-layered double hydroxide quantum dots (LDH-QDs) deposited with nitrogen-doped graphene (NG) as a bifunctional separator for lithium−sulfur batteries (LSBs). The mesoporous LDH-QDs/ NG hybrids possess abundant active sites of Co 2+ and hydroxide groups, which result in capturing LiPSs through strong chemical interactions and accelerating the redox kinetics of the conversion reaction, as confirmed through X-ray photoelectron spectroscopy, adsorption tests, Li 2 S nucleation tests, and electrokinetic analyses of the LiPS conversion. The resulting LDH-QDs/NG hybridcoated polypropylene (LDH-QDs/NG/PP) separator, with an average thickness of ∼17 μm, has a high ionic conductivity of 2.67 mS cm −1 . Consequently, the LSB cells with the LDH-QDs/NG/PP separator can deliver a high discharge capacity of 1227.48 mAh g −1 at 0.1C along with a low capacity decay rate of 0.041% per cycle over 1200 cycles at 1.0C.

Hierarchical ReS 2 / nitrogen‐doped graphene hybrid nanoarchitectures for efficient oxygen reduction

“…The high‐resolution C 1s XPS spectra presents four characteristic peaks at 284.5, 286.1, 287.3 and 288.6 eV, which are assigned to carbon in C=C, C‐O, C‐N, and O‐C=O bonds, respectively (Figure 3C). 27,48‐49 These results indicate that the oxygen‐containing functional groups of NRGO are associated with the formation of Re‐O bonds between ReS 2 and NRGO, leading to the vertical growth of ReS 2 nanosheets onto the NRGO surface for the construction of 3D hierarchical architectures 29 . Moreover, the high‐resolution N 1s XPS spectra are fitted and divided into three peaks (Figure 3D), where the peak at 398.2 eV corresponds to the pyridinic N and the peaks at 399.7 and 401.4 eV are assigned to pyrrolic N and graphitic N, respectively 50 .…”

NiFe ‐layered double hydroxide nanosheets grafted onto carbon nanotubes for functional separator of lithium sulfur batteries

“…XPS spectra of the NiFe‐LDH@OCNT before and after the adsorption experiment of Li 2 S 6 were analyzed to understand the LiPSs inhibition mechanism 23,24 . In Figure 4C, the Fe 2p 3/2 peaks of the original NiFe‐LDH@OCNT located at 711.29, 713.19, and 714.13 eV were attributed to the characteristic peaks of Fe 2+ , Fe 3+ , and shakeup satellites (abbreviated as “sat.”), respectively 25‐29 . For NiFe‐LDH@OCNT, the peaks of Fe 2+ and Fe 3+ shifted to 711.06 and 712.95 eV, respectively, after the adsorption of Li 2 S 6 .…”

“…"), respectively. [25][26][27][28][29] For NiFe-LDH@OCNT, the peaks of Fe 2+ and Fe 3+ shifted to 711.06 and 712.95 eV, respectively, after the adsorption of Li 2 S 6 . Figure 4D shows that the Ni 2p 3/2 peaks of the original NiFe-LDH@OCNT were detected at 856.87, 858.89, and 862.64 eV, which were attributed to Ni 2+ , Ni 3+ , and sat., respectively.…”

Recent progress in quantum dots based nanocomposite electrodes for rechargeable monovalent metal-ion and lithium metal batteries

“…In contrast, the control study with only the MWCNT coated PP separator showed a lower initial specific capacity of 1126.1 mA h g −1 , accompanied by comparatively faster capacity decay with only 480 mA h g −1 specific capacity retention over 500 cycles. Recently, Liu et al 235 demonstrated a Co–Al layered double hydroxide (LDH) QDs@N-doped graphene (NG) modified PP separator in a Li–S battery. The Co 2+ and hydroxide groups of LDH offer strong chemical interaction with LiPSs to prevent polysulfide shuttling, simultaneously accelerating the redox reaction kinetics.…”