All-optical spiking neural network and optical spike-time-dependent plasticity based on the self-pulsing effect within a micro-ring resonator.

In this paper, we proposed an all-optical version of photonic spiking neurons and spike-time-dependent plasticity (STDP) based on the nonlinear optical effects within a micro-ring resonator. In this system, the self-pulsing effect was exploited to implement threshold control, and the equivalent pulse energy required for spiking, calculated by multiplying the input pulse power amplitude with its duration, was about 14.1 pJ. The positive performance of the neurons in the excitability and cascadability tests validated the feasibility of this scheme. Furthermore, two simulations were performed to demonstrate that such an all-optical spiking neural network incorporated with STDP could run stably on a stochastic topology. The essence of such an all-optical spiking neural network is a nonlinear spiking dynamical system that combines the advantages of photonics and spiking neural networks (SNNs), promising access to the high speed and lower consumption inherent to optical systems.

Optimal Quantity of Nano-Silicon for Electrospun Silicon/Carbon Fibers as High Capacity Anodes.

In this study, silicon/carbon composite nanofibers (Si@CNFs) were prepared as electrode materials for lithium-ion batteries via a simple electrospinning method and then subjected to heat treatment. The morphology and structure of these materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the structure provides good electrical conductivity and affords sufficient space to accommodate volume expansion during charging/discharging. Furtherly, electrochemical performance tests show that the optimized Si@CNFs have an initial reversible capacity of 1,820 mAh g-1 at a current density of 400 mA g-1 and capacity retention of 80.7% after 100 cycles at a current density of 800 mA g-1. Interestingly, the optimized Si@CNFs have a superior capacity of 1,000 mAh g-1 (400 mA g-1) than others, which is attributed to the carbon substrate nanofiber being able to accommodate the volume expansion of Si. The SEI resistance generated by the Si@CNFs samples is smaller than that of the Si nanoparticles, which confirms that SEI film generated from the Si@CNFs is much thinner than that from the Si nanoparticles. In addition, the connected carbon substrate nanofiber can form a fiber network to enhance the electronic conductivity.

Electrochemical Analysis for Enhancing Interface Layer of Spinel LiNi0.5Mn1.5O4 Using p-Toluenesulfonyl Isocyanate as Electrolyte Additive.

LiNi0.5Mn1.5O4 (LNMO) is a potential cathode material for lithium-ion batteries with outstanding energy density and high voltage plateau (>4.7 V). However, the interfacial side reaction between LNMO and the liquid electrolyte seriously causes capacity fading during cycling at the high voltage. Here, p-toluenesulfonyl isocyanate (PTSI) is used as the electrolyte additive to overcome the above problem of LNMO. The results show that the specific capacity of LNMO/Li cell with 0.5 wt.% PTSI at the first cycle is effectively enhanced by 36.0 mAh/g and has better cycling performance than that without PTSI at 4.98 V. Also, a stable solid electrolyte interface (SEI) film derived from PTSI is generated on the electrode surface, which could alleviate the strike of hydrofluoric acid (HF) caused by electrolyte decomposition. These results are explained by the molecular structure of PTSI, which contains SO3. The S=O groups can delocalize the nitrogen nucleus to block the reactivity of PF5.