Three-Dimensional Hierarchical Porous Structure of PPy/Porous-Graphene to Encapsulate Polysulfides for Lithium/Sulfur Batteries

Herein, we demonstrate the fabrication of a three-dimensional (3D) polypyrrole-coatedporous graphene (PPy/PG) composite through in-situ polymerization of pyrrole monomer on PG surface. The PPy/PG displays a 3D hierarchical porous structure and the resulting PPy/PG hybrid serves as a conductive trap to lithium polysulfides enhancing the electrochemical performances. Owing to the superior conductivity and peculiar structure, a high initial discharge capacity of 1020 mAh g−1 and the reversible capacity of 802 mAh g−1 over 200 cycles are obtained for the S/PPy/PG cathode at 0.1 C, remaining the remarkable cyclic stability. In addition, the S/PPy/PG cathodes demonstrate an excellent rate performance exhibiting 477 mAh g−1 at 2 C

LiMnPO4 olivine as a cathode for lithium batteries

The olivine structured mixed lithium-transition metal phosphates LiMPO4 (M = Fe, Mn, Co) have attracted tremendous attention of many research teams worldwide as a promising cathode materials for lithium batteries. Among them, lithium manganese phosphate LiMnPO4 is the most promising considering its high theoretical capacity and operating voltage, low cost and environmental safety. Various techniques were applied to prepare this perspective cathode for lithium batteries. The solution based synthetic routes such as spray pyrolysis, precipitation, sol-gel, hydrothermal and polyol synthesis allow preparing nanostructured powders of LiMnPO4 with enhanced electrochemical properties, which is mostly attributed to the higher chemical homogeneity and narrow particle size distribution of the material. Up-to-date, the LiMnPO4/C composites prepared by the spray pyrolysis route have the best electrochemical performance among the reported in the literature

Optimization of deposition parameters for thin film lithium phosphorus oxynitride (LiPON)

Thin film of lithium phosphorus oxynitride (Lipon) was successfully deposited by radio frequency (RF) magnetron sputtering technique from Li3PO4 target. The power on the target was 150 W and optimal deposition pressure of N2/Ar = ~3/1 was of 2 mTorr. Analysis of the film was done by AFM, FTIR and Raman spectroscopy, which showed incorporation of nitrogen into the film as both triply, Nt, and doubly, Nd, coordinated form. The impedance spectroscopy measurements was carried out and revealed the ionic conductivity of the sample to be 8.6 × 10 − 8 S cm-1 for optimum RF power and gas flow conditions. The electrochemical properties investigations and further development of this work will be presented at the Meeting

Thermal management of LI-ION battery packs

A design for the thermal management of Lithium-ion battery packing as used in hybrid and electric vehicles has been developed. The design satisfies all thermal and physical issues relating to the battery packs used in vehicles including operating temperature range and volume, and, should increase battery cycle life, and, charge and discharge performances. Particular attention was devoted to the thermal management of batteries operating in extreme temperature conditions

A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte

A novel sulfur/graphene nanosheet (S/GNS) composite was prepared via a simple ball milling of sulfur with commercial multi-layer graphene nanosheet, followed by a heat treatment. High-resolution transmission and scanning electronic microscopy observations showed the formation of irregularly interlaced nanosheet-like structure consisting of graphene with uniform sulfur coating on its surface. The electrochemical properties of the resulting composite cathode were investigated in a lithium cell with a gel polymer electrolyte (GPE) prepared by trapping 1 mol dm−3 solution of lithium bistrifluoromethanesulfonamide in tetraethylene glycol dimethyl ether in a polymer matrix composed of poly(vinylidene fluoride-co-hexafluoropropylene)/poly(methylmethacrylate)/silicon dioxide (PVDF-HFP/PMMA/SiO2). The GPE battery delivered reversible discharge capacities of 809 and 413 mAh g−1 at the 1st and 50th cycles at 0.2C, respectively, along with a high coulombic efficiency over 50 cycles. This performance enhancement of the cell was attributed to the suppression of the polysulfide shuttle effect by a collective effect of S/GNS composite cathode and GPE, providing a higher sulfur utilization

Flexible Composite of S/PAN/C Nanofibers by Electrospinning as Binder–Free Cathodes for Li-S Batteries

As one of the most promising energy storage devices, lithium-ion batteries (LIBs) have attracted tremendous attention for its high volumetric and gravimetric energy density, no memory effects, good shape versatility, and relatively slow self-discharge rates. Conventional LIBs based on intercalation cathodes, have limited energy densities. Therefore, lithium/sulfur (Li/S) battery is considered as an attractive and promising candidate to be utilized for the mentioned purposes, which is due to its high theoretical specific capacity of 1672 mAh g− 1 and theoretical energy density of 2600 Wh kg-1 [1,2]. However, practical application of Li/S batteries is hindered by several drawbacks as: the electrical-insulating nature of sulfur results in its low utilization; lithium polysulfides intermediate products of electrochemical process are easily soluble into the organic electrolytes, which leads to severe capacity fading and low coulombic efficiency

Thermal modelling of a lithium-Ion aqueous battery

Thermal modelling is presented here for a novel lithium-ion aqueous battery [1] using the commercial multi-physics package COMSOL with extensions consisting of an energy balance and temperature dependence of properties of the battery. The model is based on the pseudo two-dimensional Doyle-Fuller- Newman (DFN) [2, 3] battery model and a thermal, electrochemistry coupled model, which can capture highrate transient effects and makes the task of relating model parameters back to physical quantities, such as diffusivity and porosity relatively easy

Vanadium based cathode materials for Aqueous Batteries

Lithium ion batteries have become the main stream for energy storage; however, its toxicity, poor durability (≤5 years) and high cost (≥USD2.35/Wh every 25 years), along with the safety issues (very high degree of reactivity with water, flammable organic solvent) make them difficult to use in smart grids..

Effectiveness of a Helix Tube to Water Cool a Battery Module

This chapter presents an investigation of the effectiveness of water cooling a battery module using a heat-sink prototype in the form of a thin copper helix tube within an aluminium block. A thermal model for the module containing six single cells is developed and numerically solved by coupling the heat energy transport equation with the fluid governing equations. The rate of generation of heat from the cells is calculated using a 2D model of a single cell with the resulting heat flux used as a Neumann boundary condition for the energy equation within a computational fluid dynamics code. Particular attention is given to the battery module operating in extreme ambient temperature conditions. The cooling strategy used is shown to satisfy two of the main concerns when managing the thermal performance of a battery module, that is, a suitable operating temperature range is maintained, and there is reasonable uniformity of temperature across the battery module. This should increase the battery cell life cycle together with enhancement of the charge and discharge performances. Variation of parameters such as the velocity of water within the tube and the number of turns used for the helix were investigated

Development of innovative lithium metal-free lithium-ion sulfur battery for renewable energy, electric transport and electronics

Lithium/sulfur (Li/S) battery is a promising candidate for the next generation rechargeable battery since the negative electrode, lithium, and the cathode, sulfur, have the highest theoretical capacities of 3862 and of 1672 mAh/g, respectively, among any other active materials, e.g., graphite (372 mAh/g) or LiCoO2 (274 mAh/g, only about 50% is practically available). However, there are several challenging issues in order to realize the use of this type of next generation battery. First, the lithium metal anode has an intrinsic safety issue, dendrite growth that can result in internal short circuit failure. Second, the sulfur cathode is a very insulating material; therefore, sulfur-based cathodes need a large amount of conducting additives, resulting in the decrease in the practically available gravimetric capacity per the unit mass of cathode composite. Third, lithium polysulfides, reduced (discharged) forms of sulfur, dissolve into an electrolyte solution, resulting in capacity fading. For realistic battery applications, these issues from both the anode and the cathode need to be solved or mitigated. To this end, we integrate three practically possible solutions: (1) manufacture-friendly pre-lithiation of anode or cathode materials, (2) practically optimal choice of conducting agent and of the method for S/conductive-agent integration, and (3) stabilization of discharged forms of the cathode