Coin Cell Battery Research Articles

Context-Aware Collaborative Intelligence With Spatio-Temporal In-Sensor-Analytics for Efficient Communication in a Large-Area IoT Testbed

Decades of continuous scaling has reduced the energy of unit computing to virtually zero, while energy-efficient communication has remained the primary bottleneck in achieving fully energy-autonomous Internet-of-Things (IoT) nodes. This article presents and analyzes the tradeoffs between the energies required for communication and computation in a wireless sensor network, deployed in a mesh architecture over a 2400-acre university campus, and is targeted toward multisensor measurement of temperature, humidity and water nitrate concentration for smart agriculture. Several scenarios involving in-sensor analytics (ISA), collaborative intelligence (CI), and context-aware switching (CAS) of the cluster head during CI has been considered. A real-time co-optimization algorithm has been developed for minimizing the energy consumption in the network, hence maximizing the overall battery lifetime. Measurement results show that the proposed ISA consumes $\approx 467\times $ lower energy as compared to traditional Bluetooth low energy (BLE) communication, and $\approx 69500\times $ lower energy as compared with long-range (LoRa) communication. When the ISA is implemented in conjunction with LoRa, the lifetime of the node increases from a mere 4.3 h to 66.6 days with a 230-mAh coin cell battery, while preserving >99% of the total information. The CI and CAS algorithms help in extending the worst case node lifetime by an additional 50%, thereby exhibiting an overall network lifetime of $\approx 104$ days, which is >90% of the theoretical limits as posed by the leakage current present in the system, while effectively transferring information sampled every second. A Web-based monitoring system was developed to continuously archive the measured data, and for reporting real-time anomalies.

NB-IoT and GNSS All-In-One System-On-Chip Integrating RF Transceiver, 23-dBm CMOS Power Amplifier, Power Management Unit, and Clock Management System for Low Cost Solution

This article presents a fully integrated stand-alone narrowband Internet-of-Things (NB-IoT) and global navigation satellite system (GNSS) system-on-chip (SoC). It aims for an all-in-one system to integrate all necessary blocks such as an RF transceiver, a power management system (PMIP), and a clock management system and to save a bills-of-material (BOM) cost. An RF transceiver is integrated to support multi-band cellular IoT and GNSS with a CMOS RF power amplifier transmitting 23-dBm output power. A PMIP, including bucks, a boost, and low-dropout regulators (LDOs), is integrated to support coin cell or AAA battery and to support a wide input supply voltage range from 2.5 to 5 V. In addition, clock management system is embedded with a digitally controlled crystal oscillator (DCXO), a relaxation oscillator (RCO), and temperature sensor units (TSUs). It is fabricated in a standard 28-nm CMOS process and its size is 24.6 mm2. The power consumption of always-on-block is 15 $\mu \text{W}$ , and the sleep current consumption is less than 10 $\mu \text{A}$ at 3.8 V.

Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries.

The development of environmentally benign hydrometallurgical processes to treat spent lithium-ion batteries (LIBs) is a critical aspect of the electronic-waste circular economy. Herein, as an alternative to the highly explosive H2O2, discarded orange peel powder (OP) is valorized as a green reductant for the leaching of industrially produced LIBs scraps in citric acid (H3Cit) lixiviant. The reductive potential of the cellulose- and antioxidant-rich OP was validated using the 3,5-dinitrosalicylic acid and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid assays. Leaching parameters such as OP concentration (200 mg), processing temperature (100 °C), H3Cit concentration (1.5 M), reaction duration (4 h), and slurry density (25 g/mL) were systematically optimized to achieve 80-99% leaching efficiencies of Ni, Mn, Co, and Li from the LIB "black mass". Importantly, solid side-streams generated by the OP-enabled leaching displayed negligible cytotoxicity in three different human cell lines, suggesting that the process is environmentally safe. As a proof of concept, Co(OH)2 was selectively recovered from the green lixiviant and subsequently utilized to fabricate new batches of LiCoO2 (LCO) coin cell batteries. Galvanostatic charge-discharge test revealed that the regenerated batteries exhibited initial charge and discharge values of 120 and 103 mAh/g, respectively, which is comparable to the performance of commercial LCO batteries. The use of fruit peel waste to recover valuable metals from spent LIBs is an effective, ecofriendly, and sustainable strategy to minimize the environmental footprint of both waste types.

Optimizing Performance of ZnO Nanorod and Activated Carbon as a Composite Anode for Lithium-Ion Batteries

To obtain the high specific capacity anode for Lithium-ion battery with stable performance is conducted by synthesizing a composite anode of ZnO-nanorods (ZnO-NR) and as a matrix is the activated carbon (AC). In this study, ZnO-NR synthesized a process that uses basic materials hexamethylenetetramine (HMTA) and zinc oxide. Activated carbon has been activated because it has high porosity and good electrical conductivity properties. Variable used is the percentage of ZnO-NR, which is 30wt%, 40wt%, and 50wt%. Characterization of the samples was examined using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Brunauer–Emmett–Teller (BET). The battery performance of the samples was obtained by Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Charge-Discharge (CD) testing after being assembled into coin cell batteries. This study discusses the effect of adding activated carbon to ZnO NR composites. The results showed that the ZnO-NR30/AC has the highest specific capacity of 270.9 mAh g-1. According to Brunner-Emmet-Teller (BET) test, the largest surface area was 631.685 m2 g-1. Electrochemical performance is the best obtained by ZnO-NR30/AC.

High power iron phosphate cathodes by atomic layer deposition

Amorphous thin films of FePO4 and Fe4(P2O7)3 show excellent power capabilities and good stability as cathode materials in Li-ion batteries. Within our tested range of materials, 10 nm FePO4 shows the best results and can handle specific powers above 1 MW/kg. The thin films are deposited using atomic layer deposition (ALD) and we studied the growth using in situ quartz crystal microbalance (QCM) showing self-limiting growth. Their electrochemical properties were characterized as cathode materials in coin cell batteries using cyclic voltammetry (CV) and galvanostatic cycling (GC), correcting for the roughness of the substrates and addressing contributions from non-Faradaic processes.

Accidental Ingestion of Foreign Bodies in Children: Experience from Developing Countries

Introduction: Accidental ingestion of foreign bodies in children is uncommon, regardless of whether in the developed or underdeveloped countries. Reports in the United States show that the most common object is a coin. The majority of the patients are asymptomatic. As the patients are asymptomatic, most of the patients were treated conservatively as the foreign bodies pass out spontaneously. In certain cases, an endoscopy is needed to retrieve the objects. This study illustrates the experience in managing the condition in a developing country. Methods: This is a retrospective study looking into the management of accidental foreign body ingestion in the local hospital. A computer search was made into the hospital database searching for a diagnosis of foreign body ingestion between April 2017 to May 2018. The parameters of the patients were retrieved from the computer database. Patients with incomplete data were excluded Result: 14 patients were identified with the diagnosis of ingested foreign bodies. One was excluded due to incomplete data. The patients' age ranges from 1 to 10 years old with 6/13 (46%) are 3 years or below. The most common objects ingested is coin (46%) followed by coin cell battery (23%). Only in one patient, the ingested material was radiolucent (stone) which was not seen on a radiograph. The majority (76.9%) of the ingested material passed out spontaneously except in 3/13 (23%), endoscopic retrieval of the material needed to be performed. There was no patient needed exploratory laparotomy. Conclusion: Accidental ingestion of coin is still the most common objects in children. Coin cell battery which is commonly used in an electronic device is getting more common. The majority of the objects can be visualized by radiograph and in the majority of cases, the material passed out spontaneously without any intervention.

Polymer Blends of Poly(ethylene oxide) and Phosphonium Ionenes As Solid Polymer Electrolyte Membranes for Lithium Ion Batteries

Solid polymer electrolytes offer potential improvements to lithium ion batteries that include extending their operating temperature range and improving the safe use of the batteries by inhibiting lithium dendrite formation. Because solid polymer electrolytes replace traditional liquid electrolytes as the lithium ion transport medium and also act as the electrode separator, these materials must offer good ionic conductivity along with providing good interfacial contact with the electrode material. This work presents the synthesis and characterization of polymer blends comprised poly(ethylene oxide) and phosphonium ionenes. Ionenes are a class of polycation that includes positive charges within the polymer backbone. Because the positive charge is a part of the polymer chain, the spacing and distribution of these charges have a significant impact on the properties of ionenes. This research focuses on determining the role of charge spacing and distribution of charges along the backbone of phosphonium ionenes on their ability to transport lithium ions. To accomplish this, phosphonium ionenes are blended with low molecular weight poly(ethylene oxide) (e.g. less than 3,000 g/mol) at mass ratios of 20:1, 10:1, and 5:1. The resulting blended solid polymer electrolyte membranes are evaluated for their thermal, mechanical and electrochemical properties along with their charge/discharge performance in coin cell batteries. The dependence of phosphonium ionene structure as well as the composition of SPE blends will be presented.

Study of (dis)-Sodiation Mechanisms within Individual Na3V2(PO4)2F3 Cathode Crystals By 4D-STEM Phase and Orientation Mapping Using ASTAR System

A further development of the rechargeable and long-lasting ion-batteries requires a comprehensive study of a plenty of processes undergoing on micro- and nano-scale in cathode active material during battery charge/discharge cycle. The discharge process results in significant transformations of the cathode’s structure while trying to accommodate the changing conditions, such as migration of transition metals, loss of oxygen, or rearrangements of the metal−oxygen polyhedra. Thus, an experimental information about structural changes occurring at the unit cell level becomes crucial for the evolution of the electrochemical performance and degradation routes of a cathode active material. In situ transmission electron microscopy (TEM) is one the most powerful analytical tools allowing to follow structural and chemical transformations in battery active materials at nanoscale with high spatial resolution in liquid high-vapor conventional electrolytes. For instance, very recently, the changes in the unit cell structure of lithium battery cathode materials (LFP) during electrochemical cycling in liquid electrolyte were determined for nano-particles using in situ electron diffraction tomography. The same compound was earlier comprehensively studied by means of 4D-STEM (ASTAR system from NanoMegas) and other techniques available in TEM (EELS). This work demonstrated that use of ASTAR system allowed to identify the LiFePO4 and FePO4 phases in individual grains and correlate them with the crystalline orientation and the facets of the individual crystals. ASTAR system is phase and crystalline orientation mappings developed from nanobeam electron diffraction. Precession of electron beam (to reduce dynamical effects) and relatively low acquisition/total scan time (to preserve the sensitive to electron beam samples) are one of the most valuable advantages of this system, particularly in in situ electrochemical liquid TEM studies.The growing demand of the modern industry to store an increasing amount of renewable energy in a sustainable way on the one hand and concerns about future Li availability on the other hand rekindled interest for sodium-ion battery technology, owing to the natural abundance of sodium. Sodium vanadium (III) fluorophosphate, Na3V2(PO4)2F3 (NVPF), attracting great interest as a potential positive electrode for Na-ion batteries due to its exceptional rate and electrochemical cycling capabilities was chosen as an object of our study. During charge process the leaving of two Na+ ions leads to the change of vanadium oxidation state (VIII → VIII/IV → VIV) and corresponding structural transformations (Amam → I4/mmm → Cmc21) which can be registered with help of ASTAR system. Our research is aimed to couple liquid electrochemical TEM studies with ASTAR system and, thus, to observe the evolution of the insertion/de-insertion zones of Na+ ions in individual positive electrode crystals and to correlate them with structural inhomogeneities, orientations and crystalline facets. The obtained in situ observations should resolve a dispute on the models proposed to account for insertion and phase separation mechanisms: mobile phase limits, intercalation waves and domino cascades.Here, we would like to present the first results of our TEM studies of NVPF. In our work we employed Poseidon in situ electrochemical liquid cell TEM holder (Protochips) and TECNAI G2 transmission electron microscope equipped with Oneview camera (GATAN) and ASTAR system. Thanks to 4D-STEM system we succeeded to follow the structural and, thus, phase transformations of NVPF grains during charge/discharge process in coin-cell battery. The results of obtained phase mapping are in a good agreement with corresponding galvanostatic curves and available X-ray diffraction synchrotron data.

Segmented Phosphonium Ionenes As Solid Polymer Electrolytes for Lithium Ion Batteries

All-solid-state lithium ion batteries replace the traditional liquid electrolyte with a conductive solid polymer electrolyte. Replacing the liquid electrolyte in batteries has the potential to improve safe use of batteries without the need for hermetic sealing, extending the operating temperature range, and extending the lifetime of the battery. However, solid polymer electrolytes often have non-competitive conductivity compared to liquid electrolytes. Improving the conductivity of solid polymer electrolytes based on an understanding of structure-property relationships is not yet well understood, but it is believed to depend heavily on the localized segmental motion of polymer chains. This work attempts to describe the role of polymer segmental motion on lithium ion transport through the synthesis and characterization of phosphonium ionenes that include poly(ethylene oxide) “soft” segments. Synthetically, these segmented polymers offer an opportunity to systematically control the segmental motion of polymer chains (i.e. glass transition temperature) through control of PEO incorporation. Prepared by step-growth polymerization, these segmented phosphonium ionenes achieve molecular weights up to 40,000 g/mol. Also, the degradation and glass transition temperatures are dependent on the percent incorporation of PEO as determined by thermogravimetric analysis and differential scanning calorimetry, respectively. The ability to influence the physical properties of this unique class of polyelectrolyte provides a unique opportunity to systematically probe the impact of glass transition temperature on the ion transport properties of solid polymer electrolytes in lithium ion batteries. Our initial results from electrochemical impedance as well as the charge/discharge performance of these novel solid polymer electrolytes in coin cell battery assemblies will also be presented.

Influence Comparison of Precursors on LiFePO4/C Cathode Structure for Lithium Ion Batteries

<p>Electricity is the most energy demanded in this era. Energy storage devices must be able to store long-term and portable. A lithium ion battery is a type of battery that has been occupied in a secondary battery market. Lithium iron phosphate / LiFePO<sub>4</sub> is a type of cathode material in ion lithium batteries that is very well known for its environmental friendliness and low prices. LiFePO<sub>4</sub>/C powder can be obtained from the solid state method. In this study the variables used were the types of precursors : iron sulfate (FeSO<sub>4</sub>), iron oxalate (FeC<sub>2</sub>O<sub>4</sub>) and FeSO<sub>4</sub>+charcoal. Synthesis of LiFePO<sub>4</sub>/C powder using Li:Fe:P at 1:1:1 %mol. Based on the XRD results, LiFePO<sub>4</sub>/C from FeSO<sub>4</sub>+charcoal shows the LiFePO<sub>4</sub>/C peaks according to the JCPDS Card with slight impurities when compared to other precursors. XRD results of LiFePO<sub>4</sub>/C with precursors of FeSO<sub>4</sub> or FeC<sub>2</sub>O<sub>4</sub> shows more impurities peaks. This LiFePO<sub>4</sub>/C cathode is paired with lithium metal anode, activated by a separator, LiPF<sub>6</sub> as electrolyte. Then this arrangement is assembled become a coin cell battery. Based on the electrochemical results, Initial discharge capacity of LiFePO<sub>4</sub>/C from the FeSO<sub>4</sub> precursor is 19.72 mAh/g, while LiFePO<sub>4</sub>/C with the FeC<sub>2</sub>O<sub>4</sub> precursor can obtain initial discharge capacity of 17.99 mAh/g, and LiFePO<sub>4</sub>/C with FeSO<sub>4</sub>+charcoal exhibit initial discharge capacity of 21.36 mAh/g. This means that the presence of charcoal helps glucose and nitrogen gas as reducing agents.</p>

Li-ion battery cathode performance from the electrospun binary LiCoO2 to ternary Li2CoTi3O8

Metal oxide nanofibers are prepared by electrospinning and are developed to be the electrodes for lithium-ion batteries (LIBs). The effect of calcination temperature and the Li:Co mole ratio of LiCoO2 nanofibers was investigated on the electrochemical cathode performance in a coin cell battery. The higher temperature calcination and Li:Co mole ratio have improved the electrochemical performance of the nanofibers. Lithium cobalt oxide (LiCoO2) nanofibers obtained at 400 and 700 °C retain 65% and 90% of the initial capacity, respectively, after the high-current test and the C-rate reverted to 0.1 C. When doubling the mole ratio of Li:Co (2:1), an increase in specific capacity values from 78 to 148 mAh g−1 has been provided. Additionally, colloidal titania nanoparticles (TiO2 NPs)-doped LiCoO2 nanofibers were obtained and investigated as a cathode material. While the increment in calcination temperature results in higher crystallinity and stability of the LiCoO2 phase, in the presence of the TiO2 NPs causes a transformation of binary (LiCoO2/TiO2) to ternary Li-based transition metal oxide (Li2CoTi3O8/TiO2). An initial discharge capacity of 82 mAh g−1 was found at 0.1 C for the Li2CoTi3O8/TiO2 nanoparticles and the capacity retention was 83% when returned to 0.1 C after 25 cycles.

Thermal Abuse Behavior of the LIR2450 Micro Coin Cell Battery Having Capacity of 120 mAh with Internal Short Circuit by Penetrating Element

Internal short circuit in lithium-ion battery by penetrating element leads to exothermic behavior due to accumulated heat. In the present study, investigations are conducted on the thermal behavior of the LIR2450 micro coin cell haivng capacity of 120 mAh, with internal short circuit by penetrating element. The experimental coin cell discharge study was conducted and validated with numerical study within ±5.0%. The effect of penetrating element size, location of penetrating element, state of charge, discharge rate, short-circuit resistance, and heat transfer co-efficient on maximum coin cell temperature and heat generation rate are analyzed. The penetrating element diameters of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 mm are considered. The effect of initial state of charge (SOC) is considered with 100%, 80%, 60%, and 40%. Three locations for penetrating element are considered with the center, the middle of the radius, and on the edge of the coin cell radius. The different discharge rates of 1C, 2C, 3C, and 4C are considered. The higher-penetrating element size of 3.5 mm with location at the center of the coin cell with 100% SOC showed maximum heat generation rate and maximum temperature of the coin cell. In addition, the optimum value of the dimensionless heat generation rate is obtained at dimensionless short-circuit resistance. The study provides comprehensive insights on the thermal behavior of the lithium-ion cell during thermal abuse condition with internal short circuit by penetrating element.

3D Localization for Sub-Centimeter Sized Devices

Recent years have seen significant advances in wireless localization [1,2]. However, existing solutions do not meet the requirements for size-constrained IoT applications. The battery life of common radio technologies, such as BLE, LoRa, ultra-wideband (UWB) and Wi-Fi, is less than 5 months when run with small coin and button cell batteries. This shorter battery life limits the adoption of tracking solutions based on these radio technologies by making them inconvenient for consumer applications and infeasible for large scale commercial deployments. Requiring large batteries, on the other hand, prevents scaling down the size of IoT devices. While RFID tags are attractive from a power and size perspective, they have a limited range and do not work consistently through walls and other barriers. Consumers often deploy devices in rooms throughout homes and, similarly, commercial deployments in settings like hospitals require covering multiple patient rooms with a variety of obstructions and walls. Achieving localization in these scenarios would therefore require readers in every room, which significantly increases deployment cost.

Neutron tomography study of a lithium-ion coin battery

Neutron imaging of lithium-ion coin cell battery was obtained using tomography technique at Neutron Scattering Laboratory in Multi-Purpose Research Reactor G. A. Siwabessy (RSG-GAS) Serpong facility. The coin cell battery was CR2032 (20d x 3.2t mm) type consisted of positive and negative cases made of stainless steel, a cathode layer from lithium Ferro phosphate coated on aluminum foil, polyethylene film as separator, lithium hexafluorophosphate solution in ethylene carbonate and diethyl carbonate as electrolyte, an anode layer from graphite coated on copper foil, and spacer as well as spring made of stainless steel. The neutron tomography was used to observe the inside structure of the full charged coin cell. The observation was carried out with a neutron flux of 107 n/s.cm2 at 15 MWatt of reactor power. The image of the object is obtained by a Charge Coupled Detector (CCD) and the reconstruction software based on a filtered back-projection algorithm. The neutron imaging clearly shows the cell structure inside the casing. Even though the cell is not at the center of the casing, but it appears that the cell component consists of a cathode, separator and anode neatly arranged. The cross-cut image shows the important role of spring and spacer in improving the contact between cell and casing. The results showed the ability of neutron tomography techniques at RSG-GAS to investigate in detail the inside structure of a coin battery without disassembly (non-destructive test).

Implantable cathodic voltage controlled electrical stimulator

This work reports the first of its kind custom implantable cathodic voltage controlled electrical stimulator (iCVCES) for use with implanted orthopaedic devices. The iCVCES allows researchers to study DC cathodic voltage controlled electrical stimulation (CVCES) in vivo with no percutaneous leads. The iCVCES is a microcontroller-based potentiostat circuit with wireless (bluetooth) communication that controls the DC cathodic stimulation and monitors the environment around the implant. Comprising a single PCB with a coin cell battery, the device is able to hold a constant voltage as large as -1.8 V in a dynamic impedance environment. In vitro tests demonstrate functionality comparable to bench-top systems, and in vivo tests demonstrate operation in live rats, for up to 8 days, with the ability to provide constant stimulation with a maximum variation of 2 mV.

Interactive on smart classroom system using beacon technology

The emergence of many internet industries ushers in IOT era, and about to bring us to the point of universal connectivity. In the field of education, the IOT technology has a broad applicable prospect for a more interactive and intelligent way by improving the quality of teaching and management. The proposed class affair management system is mean to enrich the interaction between lecturers and students which in an efficient and smart way. Based on the existing model, a layered architecture is proposed to build the beacon based campus management system. Backend device and protocols compose the physical layer to collect the raw data from physical objects. Data link layer and control layer are responsible for forming required package and sending to corresponding layer. Beacon technology used for proposed design applies Bluetooth low energy 4.0 standard which allowing devices exchange data through Bluetooth at an extremely low power consumption-using a single coin cell battery can last for several years. Saved up to 97 percentage energy compared with similar system. The entire proposed platform allows participants to bring personally owned devices to access campus management system. Through location information, teaching activities and personalized information notification can be automatically accomplished, which will inspire the innovation and development of classroom teaching mode. Beacon technology has a great potential that can be completely transplanted into other scenario such as the hypermarket and library.

Ion dynamics, rheology and electrochemical performance of UV cross-linked gel polymer electrolyte for Li-ion battery

The structural, vibrational, thermal, rheological, electrical, and dielectric properties of a series of UV cross-linked gel polymer electrolyte membranes, comprising ionic liquid, carbonate plasticizers, and lithium tetrafluoroborate salt, are investigated using x-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, rheology, and broadband dielectric spectroscopy. Rheological studies suggest that the synthesized gel polymer electrolyte membranes exhibit stable elastic behavior. The ionic transport mechanism and relaxation dynamics are systematically studied using broadband dielectric spectroscopy. The conductivity of these semi-interpenetrating polymer network based gel polymer electrolytes is found to be ∼10−3 S cm−1. The composition, which shows the highest conductivity value of 6.69×10−3 S cm−1 at ambient temperature, is also mechanically very much stable at a yield stress of 872 Pa. Hence, this gel polymer electrolyte is worthy of the device fabrication. Finally, coin cell batteries are fabricated using these gel polymer electrolyte membranes and their electrochemical performance is analyzed using electrochemical impedance spectroscopy. The optimized gel polymer electrolyte membrane shows long-term oxidative stability against lithium. The batteries also exhibit excellent cyclability.

Effect of polymer binders on the electrochemical Performance of Al-doped lithium titanate electrode

The investigation of polymers as binders of Al doped Li4Ti5O12 for Li-ion battery electrode is reported. Polimer binders such as Polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and Polytetrafluoroethylene (PTFE) were used to make electrode sheet. Al doped Lithium Titanate (Al-doped Li4Ti5O12) were used as electrode powders. Al doped Li4Ti5O12 powders were synthesized from LiOH.H2O, TiO2 and Al2O3 via solid state reaction. X-ray diffraction (XRD) was used to analysed phase and size of particle. Electrode sheets were manufactured by used active material, binders, and acetylene black in ratio 85:10:5 wt%. Electrode sheets were cut and assembled into coin cell batteries. Coin cell samples were characterized by EIS, cyclic voltammetry and charge-discharge to get electrochemical performance. XRD result reveals that there are two phases formed from final product such as Li4Ti5O12 and rutile TiO2. EIS diagram showed that sample with PTFE binder has the best conductivity with 3.10−5 S/cm. While, cyclic voltammetry and charge-discharge test showed sample with PVDF binder has the best chemical performance with good redox peaks and highest specific capacity about 110 mAh/g.

Silica-Based Ionogels Deposited By Spray Coating for All-Solid-State Lithium-Ion Microbatteries

The emerging market of the Internet of Things, smart objects and others increase the demand for micro energy sources. Rechargeable Li-ion batteries are a well-known technology for energy storage. However, safety issues and high production costs constrain progress. Research on solid electrolytes, such as LiPON, was performed to evade leakage. But LiPON suffers from low ionic conductivity and a cost and time intensive production process. Another approach is the substitution of volatile and flammable organic electrolyte solvents with ionic liquids (IL), which display negligible vapor pressure and wide chemical, electrochemical, and thermal stability. Electrolyte solution based on ILs can be confined into inorganic porous networks forming so-called ionogels (IG), which are investigated as solid electrolyte materials. IGs combine low hazard and good ionic conductivity [1]. Silica-based IGs compatible with Li/LiCoO2 systems were prepared in a one-pot sol-gel process. The composition of the IG precursor solution and the influence of trifluoroacetic acid as catalyst were studied to obtain a fast condensation. Homogeneous and transparent IGs were obtained with a gelation time of less than 12 h. The physical properties of the host matrix were characterized by N2 sorption and SEM. The silica host matrix is a 3D network predominantly built from 3-fold condensed silicon centres. Its structure changes from densely packed silica particles to open porous architecture. The electrochemical performances of the IG deposited by spray coating under ambient contitions were evaluated by impedance spectroscopy measurements. First results show that these promising IGs may be successfully used as electrolyte in Li/LiCoO2 cells, with ionic conductivities up to 0.15 mScm-1. The coin cell batteries prepared with our IGs did not show dendritic growth after more than 100 cycles of galvanostatic cycling at a C/4 rate.

(Invited) Surface Modified Polypropylene Membrane for High Performance Lithium Metal Coin and Pouch Cell Batteries

For the advanced Li metal batteries, lithium (Li) metal is considered as anode electrode because of its lowest redox potential (–3.04 V vs. standard hydrogen electrode), highest theoretical specific capacity (3,860 mAh g-1), and the low density (0.59 g cm-3). Nevertheless, Li metal anode seriously impede its practical use for viable market because of short-circuit based safety risk associated to dendrite growth and low Coulombic efficiency. Understanding those fundamental challenges, we designed a multifunctional tri-layer membrane by percolating a layer of a polydopamine (PDA) followed by depositing graphene-carboxymethyl cellulose (Gr-CMC) on the top of polypropylene (PP) separator, hypothesizing to improve the cycle stability and performance of Li metal electrodes. The novel, new trilayer comprising Gr-CMC layer of the designed separator depicted an excellent electrolyte wettability, an additional capacity of Li storage and an enhanced electrical conductivity. In Li/Cu half-cell the Coulombic efficiency was significantly enhanced over 200 cycles after implementing PDA/Gr-CMC separator. LiFePO4 cathode vs Li full cell with trilayer separator directed to long term cycle retention (1000 cycles) with enhanced rate capability. Apart from room temperature, electrochemical stability at 0 oC demonstrated the sanguine potential of PDA/Gr-CMC separator for practical Li-metal batteries. Beyond coin cells, pouch cell studies and cycling abilities will be demonstrated.