Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.

Li-O2 and Li-S batteries with high energy storage.

The Li-S battery has been under intense scrutiny for over two decades, as it offers the possibility of high gravimetric capacities and theoretical energy densities ranging up to a factor of five beyond conventional Li-ion systems. Herein, we report the feasibility to approach such capacities by creating highly ordered interwoven composites. The conductive mesoporous carbon framework precisely constrains sulphur nanofiller growth within its channels and generates essential electrical contact to the insulating sulphur. The structure provides access to Li+ ingress/egress for reactivity with the sulphur, and we speculate that the kinetic inhibition to diffusion within the framework and the sorption properties of the carbon aid in trapping the polysulphides formed during redox. Polymer modification of the carbon surface further provides a chemical gradient that retards diffusion of these large anions out of the electrode, thus facilitating more complete reaction. Reversible capacities up to 1,320 mA h g(-1) are attained. The assembly process is simple and broadly applicable, conceptually providing new opportunities for materials scientists for tailored design that can be extended to many different electrode materials.

http://dns2.asia.edu.tw/~ysho/YSHO-English/1000%20WC/PDF/Nat%20Mat8,%20500.pdf

A highly ordered nanostructured carbon–sulphur cathode for lithium–sulphur batteries

Rechargeable lithium-sulfur batteries.

We report the synthesis of a graphene–sulfur composite material by wrapping poly(ethylene glycol) (PEG) coated submicrometer sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates, and rendering the sulfur particles electrically conducting. The resulting graphene–sulfur composite showed high and stable specific capacities up to ∼600 mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.

/pdf/graphene-wrapped-sulfur-particles-as-a-rechargeable-lithium-3e7t1wglba.pdf

Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium–Sulfur Battery Cathode Material with High Capacity and Cycling Stability

Rechargeable Li–S batteries have received ever-increasing attention recently due to their high theoretical specific energy density, which is 3 to 5 times higher than that of Li ion batteries based on intercalation reactions. Li–S batteries may represent a next-generation energy storage system, particularly for large scale applications. The obstacles to realize this high energy density mainly include high internal resistance, self-discharge and rapid capacity fading on cycling. These challenges can be met to a large degree by designing novel sulfur electrodes with “smart” nanostructures. This highlight provides an overview of major developments of positive electrodes based on this concept.

Advances in Li–S batteries

Novel nanosized adsorbing sulfur composite cathode materials for the advanced secondary lithium batteries

Research on state of health prediction model for lithium batteries based on actual diverse data

To effectively resolve the automatic recognition of analog pointer measuring instruments, a reading recognition method based on Hough transform is proposed. In order to simplify the following procedure, image graying and binary, mathematical morphology, including dilation and thinning, edge recognition was applied to the system. We proposed the recognition principle for reading recognition of the pointer's angle by using Hough transform. And the reading of the pointer is decided by the linear relationship between the panel's scale and the angle of the instrument's dial revolutionary. Considering that in most practical cases, the panel cannot be horizontal, so the procedure of tilt correction is employed in this paper. Finally, the software is written in MATLAB. The recognition system is achieved in LabVIEW, where the front panel of the reading system is developed. The experimental results demonstrate that our method is feasible for pointer instrument recognition.

Development of an automatic reading method and software for pointer instruments

Digital microfluidic biochips (DMFBs) are increasingly important and are used for point-of-care, drug discovery, clinical diagnosis, immunoassays, etc. Pin-constrained DMFBs are an important part of digital microfluidic biochips, and they have gained increasing attention from researchers. However, many previous works have focused on the problem of electrode addressing and aimed to minimize the number of control pins in pin-constrained DMFBs. Although the number of control pins can be effectively redistributed through broadcast addressing technology, the chip reliability will be reduced if the signals are shared arbitrarily. Arbitrary signal sharing can lead to a large number of actuations for many idle electrodes, and as a result, a trapping charge or decreasing contact angle problem could occur for some electrodes, reducing the reliability of the chip. To address this problem, the appropriate electrode matching object should be carefully selected, and the influence of these factors on chip reliability should be fully considered. For this purpose, we aimed to fully consider electrode addressing and the reliability of the chip in improving the reliability of DMFBs. This paper proposed a pin addressing method based on a support vector machine (SVM) with the reliability constraint algorithm, which can fully consider the electrode addressing method and the reliability of the chip together. The proposed method achieved an average maximum number of electrode actuations that was 53.8% and 18.2% smaller than those of the baseline algorithm and the graph-based algorithm, respectively. The simulation experiment results showed that the proposed method can efficiently solve reliability problems during the DMFB design process.

/pdf/pin-addressing-method-based-on-an-svm-with-a-reliability-47x2qwxef0.pdf

Pin Addressing Method Based on an SVM With a Reliability Constraint in Digital Microfluidic Biochips

With the addition of online laboratories, distance education can become more meaningful and complete. Virtual laboratory is a high efficient tool for practical teaching assisted instruction. This paper design the virtual laboratory. Android application structure after analyzing the characteristics and the classification of virtual laboratory. It discusses the construction and system structure of network-based virtual laboratory which is used for MOOC (massive open online courses). This virtual laboratory environment goes based on conventional computer simulations and real cellphone test, which could provide the students with the flexibility to perform various experiments related to the fundamental law of physics, chemistry and et all. In this virtual laboratory APP, no matter the students or the instructor are represented as virtual characters. Assessment tools such as preview and review experiment tests are part of the laboratory environment which could provide different levels of the students at every step of the laboratory exercises. This paper presents a virtual lab established through data socket technology that enables the end user to design and implement control algorithms. Although this makes the problem more challenging, the quality of learning is also enhanced enormously.

Wenbin Zheng

Papers

Novel nanosized adsorbing sulfur composite cathode materials for the advanced secondary lithium batteries

Research on state of health prediction model for lithium batteries based on actual diverse data

Development of an automatic reading method and software for pointer instruments

Pin Addressing Method Based on an SVM With a Reliability Constraint in Digital Microfluidic Biochips

Development of virtual laboratory application structure in Android cellphone for distance learning