Lithium-sulfur batteries (LSBs) are promising candidates for next-generation high-efficiency energy storage, yet their practical implementation is seriously impeded by the parasitic shuttle effect and sluggish reaction kinetics. Herein, we develop a unique Cu, Co layered double hydroxide (CuCo-LDH) with a hollow and hierarchical structure as an advanced electrocatalyst to tackle these challenges. Combining the compositional, architectural, and chemical advantages, the as-developed CuCo-LDH enables facile charge transfer, fully exposed active interfaces, and strong interactions with polysulfides via metal–sulfur bonding. When employed in the functional separator, a reliable polysulfide barrier can be established against the shuttling behavior, while the excellent catalytic activity realizes fast and efficient sulfur electrochemistry. As a result, the CuCo-LDH-based LSBs achieve a well-restrained capacity decay of 0.049% per cycle over 500 cycles together with a good rate capability up to 5 C. Moreover, a favorable areal capacity of 4.39 mAh cm−2 and decent cyclability are still attainable even under a high sulfur loading of 4.2 mg cm−2 and a low E/S ratio of 6 ml g−1. This work affords a feasible and instructive pathway toward advanced sulfur electrocatalysts as well as high-performance LSBs.
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The development of Li-S batteries (LSBs) is hindered by the low utilization of S species and sluggish redox reaction kinetics. Polar metal oxides always possess high adsorption to polar S species, while conductive metal nitrides show fast electron transport and ensure fast redox reaction of S species. The combination merits of metal oxides and metal nitrides in one provide an effective strategy to improve the electrochemical performance of LSBs. In this work, defect design of niobium oxynitrides highly dispersed on graphene (NbON-G) is evaluated as effective trapper and catalyst for S species. Owning to the effective structural merits including enriched active sites, alleviated volume variation, defect modulated electronic property, and in-situ chemisorption and catalytic conversion of soluble lithium polysulfides (LiPSs), the LSBs with NbON-G modified separator show remarkably enhanced performance compared to NbN-G and Nb2O5-G. Surprisingly, even at low temperature of −40 °C, the LSBs with NbON-G can operate for 1,000 cycles with 0.04% capacity decay per cycle (Rate: 2 C).
Nickel(Ni)-rich layered oxide has been regarded as one of the most important cathode materials for the lithium-ion batteries because of its low cost and high energy density. However, the concerns in safety and durability of this compound are still challenging for its further development. On this account, the in-depth understanding in the structural factors determining its capacity attenuation is essential. In this review, we summarize the recent advances on the degradation mechanisms of Ni-rich layered oxide cathode. Progresses in the structure evolution of Ni-rich oxide are carefully combed in terms of inner evolution, surface evolution, and the property under thermal condition, while the state-of-the-art modification strategies are also introduced. Finally, we provide our perspective on the future directions for investigating the degradation of Ni-rich oxide cathode.
The glycerol electro-oxidation reaction (GEOR) is a green and promising method for the glyceraldehyde production. In this work, Pd nanocrystals (Pd-NCs) modified ultrathin NiO nanoplates (NiO-uNPs) hybrids (Pd-NCs/NiO-uNPs) are successfully synthesized using successive cyanogel hydrolysis, chemical reduction, and calcination treatment methods. Various electrochemical measurements and physicochemical characterization results demonstrate that Pd-NCs/NiO-uNPs hybrids have excellent electrocatalytic performance for both GEOR and hydrogen evolution reaction (HER) in alkaline medium, which benefit from the large specific surface area, uniform distribution of Pd-NCs, and the modified electronic structure of Ni atoms. At Pd-NCs/NiO-uNPs hybrids, only 1.43 V is needed to obtain the current density of 100 mA∙cm−2 for GEOR, much lower than that for oxygen evolution reaction (1.82 V). In addition, Pd-NCs/NiO-uNPs hybrids exhibit better HER performance than commercial Pd/C electrocatalyst. As a result, the constructed Pd-NCs/NiO-uNPs||Pd-NCs/NiO-uNPs glycerol electrolyzer only requires 1.62 V electrolysis voltage to reach 10 mA∙cm−2 current density, showing an energy-efficient and economy-competitive synthesis for the coproduction of glyceraldehyde and hydrogen.