In-situ formed Co nano-clusters as separator modifier and catalyst to regulate the film-like growth of Li and promote the cycling stability of lithium metal batteries.

Lithium metal batteries (LMBs) are considered a highly prospective next-generation energy storage technology. However, their large-scale commercial application is hampered by the uncontrollable growth of Li dendrites, which accompany the boundless inflation of the battery's volume. In this study, we address this challenge by fabricating a porous structure of the MOF-derived CoP nanocube film (CoP-NC@PP) as a adorned layer for the separator. During the initial cycle, this film facilitates the in situ formation of Li3P with ultrahigh ionic conductivity and a lithiophilic Co, which helps rule the nucleation and deposition behavior of lithium and stabilizes the solid-electrolyte interphase. The symmetric cell incorporating the CoP-NC@PP modified layer exhibits exceptional cycling stability, surpassing 1500 h of continuous operation. The kinetic process of Li interaction with CoP and the structural factors contributing to the high cycling stability and high naminal voltage were investigated by molecular dynamics simulation and density functional theory calculations. Furthermore, full cells employing Li||CoP-NC@PP||LFP (LFP = LiFePO4) configurations demonstrate excellent cycling stability and high capacity, even at a high rate of 5 C (≈5.2 mA cm-2), with the cathode mass loading reaching as high as 10.3 mg cm-2.

Composite NiCo2 O4 @CeO2 Microsphere as Cathode Catalyst for High-Performance Lithium-Oxygen Battery.

The large overpotential and poor cycle stability caused by inactive redox reactions are tough challenges for lithium-oxygen batteries (LOBs). Here, a composite microsphere material comprising NiCo2 O4 @CeO2 is synthesized via a hydrothermal approach followed by an annealing processing, which is acted as a high performance electrocatalyst for LOBs. The unique microstructured catalyst can provide enough catalytic surface to facilitate the barrier-free transport of oxygen as well as lithium ions. In addition, the special microsphere and porous nanoneedles structure can effectively accelerate electrolyte penetration and the reversible formation and decomposition process of Li2 O2 , while the introduction of CeO2 can increase oxygen vacancies and optimize the electronic structure of NiCo2 O4 , thereby enhancing the electron transport of the whole electrode. This kind of catalytic cathode material can effectively reduce the overpotential to only 1.07 V with remarkable cycling stability of 400 loops under 500 mA g-1 . Based on the density functional theory calculations, the origin of the enhanced electrochemical performance of NiCo2 O4 @CeO2 is clarified from the perspective of electronic structure and reaction kinetics. This work demonstrates the high efficiency of NiCo2 O4 @CeO2 as an electrocatalyst and confirms the contribution of the current design concept to the development of LOBs cathode materials.

Amorphous RuS2 electrocatalyst with optimized active sites for hydrogen evolution.

Transition metal chalcogenides have attracted much attention as high-performance electrocatalysts for hydrogen evolution reaction (HER). Here, we synthesized an efficient HER electrocatalyst of amorphous ruthenium sulfide (A-RuS2), exhibiting an overpotential of 141 mV at the current density of 10 mA cm-2 and a Tafel slope of 65.6 mV dec-1. Experiments demonstrate amorphous RuS2 has much better catalytic activity than that of its crystalline counterparts. Our study shows that amorphous RuS2 has increased intrinsic activity and active sites. This work provides a feasible strategy for the development of HER electrocatalysts in amorphous state.