Acoustic correlation current profiler (ACCP) was proposed to observe deep scattering layer (DSL). Several important parameters of ACCP could be used to observe DSL, such as the strength of the backscattering, the vertical velocity of current profile and the cross correlation function. Based on these parameters, 23 kHz prototype ACCP was used to observe DSL in sea trials in South China Sea. Results showed that it was feasible to observe DSL by ACCP.
Abstract Low-power and high-density electronic synapse is an important building block of brain-inspired systems. The recent advancement in memristor has provided an opportunity to advance electronic synapse design. However, a guideline on designing and manipulating the memristor’s analog behaviors is still lacking. In this work, we reveal that compliance current ( I comp ) of electroforming process played an important role in realizing a stable analog behavior, which is attributed to the generation of conical-type conductive filament. A proper I comp could result in a large conductance window, good stability and low voltage analog switching. We further reveal that different pulse conditions can lead to three analog behaviors, where the conductance changes in monotonic increase, plateau after initial jump and impulse-like shape, respectively. These behaviors could benefit the design of electronic synapse with enriched learning capabilities. This work will provide a useful guideline for designing and manipulating memristor as electronic synapses for brain-inspired systems.
Rational design of cost‐effective, nonprecious metal‐based catalysts with desirable oxygen reduction reaction (ORR) performance is extremely important for future fuel cell commercialization, etc. Herein, a new type of ORR catalyst of Co‐N‐doped mesoporous carbon hollow sphere (Co‐N‐mC) was developed by pyrolysis from elaborately fabricated polystyrene@polydopamine‐Co precursors. The obtained catalysts with active Co sites distributed in highly graphitized mesoporous N‐doped carbon hollow spheres exhibited outstanding ORR activity with an onset potential of 0.940 V, a half‐wave potential of 0.851 V, and a small Tafel slope of 45 mV decade −1 in 0.1 m KOH solution, which was comparable to that of the Pt/C catalyst (20%, Alfa). More importantly, they showed superior durability with little current decline (less than 4%) in the chronoamperometric evaluation over 60 000 s. These features make the Co‐N‐mC one of the best nonprecious‐metal catalysts to date for ORR in alkaline condition.
This study clarifies the heat generation and release of a 57.5 Ah HED (266.9 W h kg −1 ) Li-ion cell with a nickel-rich cathode and SiO x /graphite anode. Significant heat accumulation and delayed heat release effects in large-format cells are uncovered.
Abstract Nitrate is one of the essential raw ingredients in agriculture and industry. The electrochemical nitrogen oxidation reaction (NOR) is promising to replace the conventional nitrate synthesis industry with high energy consumption and greenhouse gas emission. Here, tensile‐strained palladium porous nanosheets (Pd‐s PNSs) were prepared. They exhibited enhanced activity for electrochemical NOR at ambient conditions, greatly outperforming Pd nanosheets. 15 N isotope labeling experiments proved that nitrate originated from nitrogen oxidation. Combining electrochemical in situ Raman and FTIR spectroscopy with density functional calculations, it was revealed that the tensile strain could facilitate the formation of NOR active species of PdO 2 , leading to high activity.
Abstract Constructing a 3D lithium metal anode has been demonstrated to be the most effective strategy to address its dendrite issue in liquid batteries. However, this promising approach has proved challenging to inherit in all‐solid‐state Li metal batteries (ASSLMBs) because of the rigidity of inorganic solid electrolytes (SEs), which constrains interfacial solid–solid ionic contact. Herein, a 3D Li anode is in situ constructed for ASSLMBs by spontaneous chemical reactions between halide SEs and Li metal. The in situ formed Li–Al alloys and well‐maintained sulfide SEs inside the 3D structure serve as continuous electron and Li + transport pathways and facilitate the homogenous distribution of charge carriers. The lithiophilic Li alloy can regulate Li deposition behavior and enable uniform Li nucleation and deposition. Both the Li||Li symmetric and full batteries exhibit good electrochemical performance at high current density. This work provides a universal strategy and new insight perspective to construct 3D Li for high‐performance ASSLMBs.
Sulfide electrolytes represent a crucial category of superionic conductors for all-solid-state lithium metal batteries. Among sulfide electrolytes, glassy sulfide is highly promising due to its long-range disorder and grain-boundary-free nature. However, the lack of comprehension regarding glass formation chemistry has hindered their progress. Herein, we propose interstitial volume as the decisive factor influencing halogen dopant solubility within a glass matrix. We engineer a Li
While Li–S batteries are poised to be the next generation high-density energy storage devices, low sulfur utilization and slow rate performance have limited their practical applications. Here, we report the synthesis of monodispersed S8 nanoparticles (NPs) with different diameter and the nanosize dependent kinetic characteristics of the corresponding Li–S batteries. Most remarkably, 5 nm S NPs display the theoretical discharging/charging capacity of 1672 mAh g–1 at 0.1 C rate and a discharge capacity of 1089 mAh g–1 at 4 C.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
