Lithium Ion Secondary Batteries Research Articles

Ultrasonic Battery Management System for Lamb wave mode tracking on Lithium-ion pouch cells

During charging and discharging, lithium-ion secondary batteries (LIBs) change their mechanical properties due to intercalation and deintercalation of lithium-ions in the electrodes. In this work, a novel ultrasonic battery management system (UBMS) with dedicated FPGA hard- and software has been developed that can track these mechanical changes by using ultrasonic sensors. In particular, the group velocity of the fundamental Lamb mode A0 is tracked and compared with the proposed simulation model. Previous studies have shown that the Young’s modulus of the anode coating changes significantly during cycling. By incorporating this information into the simulation, a change in this value will drastically affect the group velocity of the propagating wave mode A0, which can also be seen in the measurements carried out. To represent a realistic use case, the behaviour of the Lamb mode A0 is measured at different temperatures, which have a big influence on the group velocity of the propagating wave mode. The collected ultrasonic BMS data was further used to develop a state-of-charge (SOC) and temperature estimator. The accuracy of this novel method is discussed. With the addition of the ultrasonic sensors, the BMS can have a larger and better database that can be used to provide a more accurate estimate of the mechanical properties of LIBs and their SOC and temperature.

Electrochemical Performance According to High-Capacity Silicon Active Materials in Lithium Ion Batteries

Carbon has been used as stable anode material for lithium-ion secondary batteries. However, instead of graphite with a low capacity, a new material with a high capacity that can increase the energy density per volume or mass of a lithium ion secondary battery is required. Among the various candidates, silicon has a high capacity of about 4000 mAh/g, making it a major research subject. Graphite is a combination of 6 carbon atoms and 1 lithium ion, but silicon accepts 4.4 lithium ions per atom, resulting in high volume expansion. In this way, excessive volume expansion causes cracks in the electrode and electrochemical disconnection, which eventually leads to a decrease in battery capacity. The large volume change and low electrical conductivity of silicon limits its application to anodes. Potential silicon-based materials include silicon oxide-based (SiOx), carbon-silicon composite (SiC), and pure silicon (pure Si). Silicon-based oxides have the advantages of high capacity and stable battery life, but have the limitations of low initial efficiency and low electrical conductivity. Carbon-composite silicon has high initial efficiency, high ionic conductivity, high capacity, and can be applied in the same slurry system as existing graphite electrodes. Selection of a stable binder and conductive material is important for active use of silicon-based materials. Promising binders include polyvinyl alcohol (PVA), polyacrylic acid (PAA), and polyacrylamide (PAM), and conductive materials include single-walled carbon nano tube (SWCNT), multi-walled carbon nano tube (MWCNT), and carbon-based conductive materials. In this study, we applied poly(vinyl alcohol-co-acrylic acid) random copolymer polymer as a binder and analyzed the characteristics of silicon-based batteries with various conductive materials. Slurry analyzes such as slurry dispersibility, phase stability, and rheology were performed. The initial efficiencies and cycle performances of different types of silicon-based materials were compared. It was confirmed that the type of silicon-based negative electrode material and the type of conductive material affect battery performance.

Concentrated Electrolyte for Stable Lithium Metal Anode

Secondary lithium-ion batteries have been widely used as energy storage systems for portable electronics and electric vehicles. Instead of applying graphite as the anode, lithium (Li) metal has an ultrahigh theoretical capacity (3860 mAh/g) that could significantly increase battery’s energy density. Li dendrite formation is considered the main issue when using Li-metal anodes. Therefore, anode-free batteries are suggested as a solution to this obstacle. However, the major problem with anode-free batteries is their inferior cycling performance than reported lithium metal batteries, resulting from the formation of a fragile and fractured Solid-Electrolyte Interphase (SEI).To establish a robust SEI, novel lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) and LiNO3-based electrolytes with four different ratios were prepared in the co-solvent system (1,3-dioxolane and 1,2-dimethoxyethane). Compared to the other three electrolytes, concentrated electrolyte (4M LiTFSI + 2 wt.% LiNO3 or 4+2) in Li||LiFePO4 cells indicated the highest initial discharge capacity of 154 mAh/g with a capacity retention of 78% after 50 cycles. Scanning electron microscopy was conducted to investigate the SEI morphology after the initial charge/discharge process. The deposited Li on the Li metal was highly dense, and no spiky or needle-like Li clusters were detected. Additionally, electrochemical impedance spectroscopy of the cells was measured after 1, 3, 5, and 10 cycles, respectively. The cells with 4+2 showed the smallest SEI resistance after different cycles, corresponding to a stable and less-resistive SEI formation.

Tape Casting for Development of Thermal Batteries

Thermal (thermally activated) batteries are primary batteries which operate at temperatures ranging from 350°C to 650°C. Due to its long shelf life and high power density (up to 8kW kg-1)1, thermal batteries have been used reliably for military applications such as providing back up power for aircraft hydraulics, missiles and even the Galileo probe.2 Currently, thermal batteries are manufactured by a labour intensive pellet pressing method which limits the design and thickness of the batteries. To improve the power density of thermal batteries, tape casting has been examined. Tape casting is a common method of manufacturing commercial secondary lithium-ion batteries. Tape casting enables relatively thin films of battery components to be utilized which minimises the thickness of the battery components and gives the option to alter the design of the battery itself.Despite its many years in operation for important military applications, processing of thermal batteries into functional cast films has not been achieved so far due to the high operational temperatures of thermal batteries which negate the use of standard polymers. To counter this issue, high temperature polymers, inorganic binders and carbon nanotubes have been examined for their use as binders for thermal battery component inks. Their thermal stability was examined using STA and the oxidation of pyrite was analysed through EDS and PXRD. Successful processing of the constituent battery components is hoped to drastically improve the electrochemical performance of the cell and decrease the manufacturing cost of the batteries. R. A. Guidotti, G. L. Scharrer, E. Binasiewicz and F. W. Reinhardt, 1998.R. A. Guidotti and P. Masset, J. Power Sources, 2006, 161, 1443-1449.

Polysulfide Rejection Strategy in Lithium-Sulfur Batteries Using an Ion-Conducting Gel-Polymer Interlayer Membrane.

Lithium-sulfur batteries (LiSBs) are emerging as promising alternative to conventional secondary lithium-ion batteries (LiBs) due to their high energy density, low cost, and environmental friendliness. However, preventing polysulfide dissolution is a great challenge for their commercial viability. The present work is focused on preparing a lithium salt and ionic liquid (IL) solution (SIL) impregnated ion (lithium ion)-conducting gel-polymer membrane (IC-GPM) interlayer to prevent polysulfide migration toward the anode by using an electrostatic rejection and trapping strategy. Herein, we introduce an SIL-based freestanding optimized IC-GPM70 (70 wt % SIL) interlayer membrane with high lithium-ion conductivity (2.58 × 10-3 S cm-1) along with excellent thermal stability to suppress the migration of polysulfide toward the anode and prevent polysulfide dissolution in the electrolyte. Because of the coulombic interaction, the anionic groups, -CF2 of the β-phase polymer host PVdF-HFP, TFSI- anion of IL EMIMTFSI, and anion BOB- of LIBOB salt, allow hopping of positively charged lithium ions (Li+) but reject negatively charged and relatively large-sized polysulfide anions (Sx-2, 4 <x <8). The cationic group EMIM+ of the IL is electrostatically able to attract and trap the polysulfides in the interlayer membrane. Since the shuttle effect of lithium polysulfides in LiSBs has been suppressed by the prepared IC-GPM70 interlayer, the resulting lithium-sulfur cell exhibits significantly higher cycling stability (1200 cycles), rate performance (1343, 1208, 1043, 875, and 662 mAh g-1 at 0.1C, 0.2C, 0.5C, 1C, and 2C, respectively), and structural integrity during cycling than its counterpart without the IC-GPM70 interlayer. The interlayer membrane has been found to improve the performance and durability of LiSBs, thus making them a viable alternative to conventional LiBs.

Sintering-free preparation of Li7La3Zr2O12–LiBH4-based solid-state electrolytes and their electrical conductivities

Solid-state electrolytes with sintering-free characteristics and compatibility with Li metal anodes are desirable for increasing the energy density of lithium-ion secondary batteries. In this study, we developed a composite-type electrolyte two Li-metal compatible materials: conductive Li7La3Zr2O12 (LLZ) and sintering-free LiBH4. Preparation of LLZ powder by hand milling, rather than ball milling, was beneficial to produce dense LLZ–LiBH4 composite. The LLZ–LiBH4 composited mixed by hand did not exhibit the formation of secondary phases at a magic-angle-spinning nuclear magnetic resonance level. Up to a volume fraction of LLZ to 0.8, LiBH4 filled the space between LLZ particles, and the total ionic conductivity increased with increasing LLZ fraction. The LLZ–LiBH4 composite showed 670 times higher room-temperature ionic conductivity at the optimum composition than that of LiBH4 alone. The Li+ conduction behavior of the LLZ–LiBH4 composite changed from a percolation model to a series resistance model by the phase transition of LiBH4 to a high-temperature conductive phase. Furthermore, the current tolerance of Li|LLZ–LiBH4 composite|Li cell was comparable to that of a cell using a well-sintered LLZ electrolyte, suggesting that this composite can be used with Li metal anode.

Synthesis of high-voltage cathode material using the Taylor-Couette flow-based co-precipitation method.

LiNi0.5Mn1.5O4 (LNMO), a next-generation high-voltage battery material, is promising for high-energy-density and power-density lithium-ion secondary batteries. However, rapid capacity degradation occurs due to problems such as the elution of transition metals and the generation of structural distortion during cycling. Herein, a new LNMO material was synthesized using the Taylor-Couette flow-based co-precipitation method. The synthesized LNMO material consisted of secondary particles composed of primary particles with an octahedral structure and a high specific surface area. In addition, the LNMO cathode material showed less structural distortion and cation mixing as well as a high cyclability and rate performance compared with commercially available materials.

Plantar pressure-measuring device powered by flexible all-solid-state battery

Flexible or stretchable devices have been attracting attention because of the increase in popularity of internet-of-things devices and wearables. Because lithium-ion secondary batteries have rigid bulk shapes and therefore affect bodily motion, their use in such devices is problematic. Demand for plantar pressure-measuring devices has increased because impairment of ambulation leads not only to accidental falls by elderly people but also to arthritic disorders such as backaches induced by hallux valgus, calluses, and ingrown nails. Because the design of such a small, lightweight device with a medium-capacity lithium-ion battery is impossible, the collection of sufficient data has been impossible. We designed a novel all-solid-state battery produced with a solid-state electrolyte. The battery discharged even when folded, cut, or pushed. This 440 mAh battery could be used to improve overall usability of a prototype of an insole device that would consist of pressure sensors, a wireless communication device, and the battery.

Towards Highly Efficient Lithium-Ion Batteries: Focusing on Electrolytes

Lithium-ion is various advantages and is required by batteries such as high power, so lithium-ion plays a crucial role in lithium-ion batteries. The electrolyte is one of the core materials of lithium secondary battery and primary battery capacity, improves the mobility between the mobile anode and cathode, and plays the role of medium material. The lithium-ion battery's electrolyte, a crucial component, transports ion conduction current between the positive and negative electrodes. Choosing the right electrolyte is also essential for achieving high energy and power densities, long cycle lives, and good safety performance of the lithium-ion secondary battery. First, understand the lithium-ion battery charge and discharge of the working principle of the chemical equation, and the lithium-ion battery is split into four key components, respectively: positive and negative electrode, diaphragm, and electrolyte, then the electrolyte analysis, the electrolyte is composed of organic solution, conductive salt, and additives. Finally, a new type of sulfate additive, ethyl sulfate, is found and studied at the electrolyte level by literature search. By using the constant current charge-discharge test, cyclic voltammetry, scanning electron microscopy, energy scattering spectroscopy, and electrochemical impedance spectroscopy, researchers are examining the effects of additive ethyl sulfate (DTD) on the performance of lithium-ion batteries and the interfacial performance of graphitized carbon microspheres (MCMB) electrode/electrolyte (EIS).

Synthesis of co-oligomers containing 1,1-Dialkyl-3,4-diphenyl-2,5-silolene and aromatic diolene and analysis of their anodic properties for lithium-ion battery

The co-oligomerization of 1,1-dialkyl-2,5-dibromo-3,4-diphenyl-siloles Ia,b with aromatic diols IIa′∼ c′ in the presence of K2CO3 and N-methyl-2-pyrrolidone/toluene as cosolvents by nucleophilic aromatic substitution yielded oligomers containing 1,1-dialkyl-3,4-diphenyl-2,5-silolene and aromatic diolene such as IIIaa′∼bc′ as brownish solids. The oligomeric materials IIIaa′∼bc′ were characterized using spectroscopic methods, such as 1H, 13C NMR, FT-IR, photoelectronic properties, and thermal stabilities. Typically, oligomers IIIac′ and IIIbc′ show good anodic properties for lithium-ion batteries, such as rate capabilities of 720 and 490 mAh/g at 0.5 A/g after the 35th cycle, charge capacities of 740 mAh/g at the 150th cycle and 500 mAh/g at the 200th cycle, and long-cycle performances of 820 mAh/g after the 157th cycle and 530 mAh/g after the 180th cycle, respectively. The anodic property of the cell fabricated with the oligomer IIIac′ Li cell was generally superior to that of the cell made with oligomer IIIbc′ and was also much higher than that of graphite. Both IIIac′ and IIIbc′ may be applicable as anodic materials in lithium-ion secondary batteries.

Cross-Border Dynamics of IP Modularity: International Patenting in LEDs and Lithium-Ion Secondary Battery Technology

To profit from their inventions, multinational enterprises rely on various appropriation and internationalization strategies. Intellectual property modularity serves as a reliable option to master the tradeoff between owning the “right” (i.e., valuable) patents in a technology and sharing other “less valuable” patents to spur innovation and foster technology dissemination. Through an inductive, multi-case approach looking at light-emitting diodes and lithium-ion secondary battery technology, we expand prior intellectual property modularity to incorporate internationalization effects across borders. Relying on patent classifications, we trace the development of these two technologies and key multinational enterprises in various countries longitudinally from 1990 to 2018. We introduce the Dynamic IP Modularity Application Matrix and demonstrate that integrating the firm and country levels yields insights into dynamic internationalization developments, particularly when considering the drawbacks to intellectual property modularity. Herein, decision-makers need to secure not only currently valuable but also potentially valuable intellectual property to successfully apply an international intellectual property modularity value capture strategy.

Air-Stable Li3SbS4-LiI Electrolytes Synthesized via an Aqueous Ion-Exchange Process and the Unique Temperature Dependence of Conductivity.

The stability of sulfide-based solid electrolytes (SEs) in ambient air is a critical criterion for the application of all-solid-state lithium-ion batteries. Air-stable Li3SbS4-LiI SEs were synthesized using a unique process in an aqueous solution under ambient air, i.e., an ion-exchange (IE) process. The crystalline structure of Li3SbS4 obtained by this process was confirmed by X-ray diffraction (XRD) patterns. The ionic conductivity of the obtained SE was 8.5 × 10-8 S cm-1 at 50 °C. The SEs of Li3SbS4-LiI were also synthesized via the IE process. The temperature dependence of the Li3SbS4-LiI SEs' ionic conductivities showed a unique behavior; for example, the conductivities of 60Li3SbS4·40LiI (LSbSI) rapidly increased upon heating from 1.8 × 10-7 S cm-1 at 26.5 °C to 8.4 × 10-3 S cm-1 at 65 °C. The LiI layers on LSbSI are responsible for the unique temperature dependence of conductivity determined by differential scanning calorimetry-XRD measurement. Further, the dehydrated LSbSI obtained by milling and annealing showed a high conductivity of 1.3 × 10-4 S cm-1 at a low temperature of 25 °C. A cathode composite containing the active material of Ti2S and the LSbSI SE obtained via the IE process was prepared by freeze-drying. The all-solid-state cell using the cathode composite, which consists of Li-In/SE/TiS2-LSbSI, showed good performance at 60 °C as a lithium-ion secondary battery.

Effect of Lithium 4-Styrene Sulfonate–Based Self-Doped Polymer Electrolyte on LiMn2O4 Electrodes in Lithium-Ion Secondary Batteries

Effect of Lithium 4-Styrene Sulfonate–Based Self-Doped Polymer Electrolyte on LiMn2O4 Electrodes in Lithium-Ion Secondary Batteries

Comparative Study on the Electrochemical Properties of Cylindrical and Pouch-Type Lithium Ion Battery

As the field expands from portable electronic devices to large energy storage devices such as electric vehicles, more reliable and innovative battery technologies are more important than ever.Currently, there are three types of lithium battery packaging: cylindrical, prismatic and pouch. Cylindrical batteries with a cylindrical shape and structure were one of the first mass-produced battery types and are still mass-produced and dominate in some applications. On the other hand, prismatic batteries are gaining popularity due to their high capacity, thin form, and efficient use of space. Due to the angular shape, multiple cells can be easily connected to form larger packs. Finally, pouch batteries are known for their lighter construction, using a sealed flexible foil as the packaging material.Each of these battery types offers a set of advantages and disadvantages. There is no clear winner, but the battery you choose can influence your product design in many ways. For example, each of these battery form factors can have a different temperature distribution and heat transfer model.In this study, a cylindrical battery and a pouch-type battery of the same capacity were manufactured using the same four major materials (positive electrode, negative electrode, separator, and electrolyte), respectively, to study the cell chemical characteristics of Li-ion secondary batteries. In particular, it is intended to provide a field to which each type of lithium ion secondary battery can be applied by understanding the characteristics of thermal and deterioration.

Laser-Induced Graphene(LIG)-Based Anode Electrode for High-Rate Lithium-Ion Batteries

The development of next-generation secondary batteries hinges on the design of energy storage materials with high-rate properties capable of high-speed charge/discharge. For example, in order to eliminate 'range anxiety,' which is one of the key problems that makes people hesitate to acquire electric vehicles, it is necessary to build a rechargeable battery that can be recharged in minutes.The high current density applied to the electrode during high-speed charging/discharging, however, generates a lithium ion concentration gradient inside the electrode, which causes a variety of issues. Furthermore, one of the key reasons for the difficulties in creating energy storage materials with high high-rate qualities is the material's inherent properties, such as ion transport restriction.We used laser processing and a dry transfer procedure to create a negative electrode plate for a lithium ion secondary battery with a surface aligned in a certain orientation. When compared to the existing electrode plate, laser-induced graphene (LIG), a porous three-dimensional nanomaterial generated by laser processing, had a higher specific surface area and a three-dimensional network structure. The fracture surface of the LIG, whose plane orientation was configured in this easy-to-transfer direction, was discovered to have a significant impact on rate capabilities.A commercially available polyimide (PI) film (thickness: 125 µm, Kapton) was used to make the LIG-based negative plate used in this investigation, which was treated with a CO2 laser with a wavelength of 10.6 µm. The irradiated laser had a power output of 5.4 W, and the scan speed and pitch were kept at 200 mm/s and 125 µm, respectively. Press-type roll forming was used to transfer the so produced LIG to a copper substrate with a thickness of around 20 µm, with the distance between the rolls controlled between 70 and 200 µm and the specimen feed rate controlled between 10-100 mm/s. For electrochemical evaluation, the negative plate was made up of 2032 typed coin cells, and for material evaluation, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used.Despite applying a high current density of 20 A/g at a loading level of around 3 mg/cm2, this electrode obtained a discharge capacity of 114 mAh/g within 3 minutes, corresponding to 95 percent of the material. The great specific surface area of nanomaterials like graphene, as well as the three-dimensional structure in which the surface is oriented in a precise direction due to dry transfer, account for the unusually high rate.In other words, the lowered internal charge transfer resistance helps to realize high rate characteristics because the holey-structured graphene with high porosity due to laser processing is well stacked in a three-dimensional structure. Furthermore, because the electrode surface is structured in a structure with multiple edge plane exposures, it was feasible to create an anode material with high rate characteristics by shortening the lithium ion transport and diffusion distance.This method can be easily applied to the current negative electrode material and electrode manufacturing process for lithium ion secondary batteries, and it has the potential to be extended and applied to material manufacturing methods for a variety of applications that improve charge and ion transport.

"Polymer-in-Ceramic" Membrane for Thermally Safe Separator Applications.

In this work, a facile casting method was utilized to prepare “polymer-in-ceramic” microporous membranes for thermally safe battery separator applications; that is, a series of composite membranes composed of silicon dioxide (SiO2) as a matrix and polyvinylidene fluoride (PVDF) as a binder were prepared. The effects of different SiO2 contents on various physical properties of membranes such as the porosity, electrolyte absorption rate, electrochemical stability, and especially thermal stability of the SiO2/PVDF composite membranes were systematically studied. Compared with a commercial polypropylene separator, the SiO2/PVDF membrane has a higher porosity (66.0%), electrolyte absorption (239%), and ion conductivity (1.0 mS·cm–1) and superior thermal stability (only 2.1% shrinkage at 200 °C for 2 h) and flame retardancy. When the content of SiO2 in the membrane reached 60% (i.e., PS6), LiFePO4/PS6/Li half-cells exhibited excellent cycle stability (138.2 mA h·g–1 discharging capacity after 100 cycles at 1C) and Coulombic efficiency (99.1%). The above advantages coupled with the potential for rapid and large-scale production reveal that the “polymer-in-ceramic” SiO2/PVDF membrane has prospective separator applications in secondary lithium-ion batteries.

Exceptionally high sodium ion conductivity and enhanced air stability in Na3SbS4 via germanium doping

In addition to the widely used lithium-ion secondary batteries, more and more concerns have been paid to solid-state batteries (SSBs) in the research on future-generation energy storage systems. The availability of sodium solid electrolytes, especially those with excellent ambient temperature conductivity and prominent chemical stability, is crucial for sodium-based SSBs. In this study, Na3.1Ge0.1Sb0.9S4, a novel sodium-ion solid-state electrolyte, was obtained via a solid-state chemical reaction utilizing the economical Na2S·9H2O as one of the raw ingredients. The properties of this new electrolyte were examined by using X-ray diffractometry, Raman spectroscopy, differential scanning calorimetry, scanning electron microscopy, and electrochemical techniques. The Na3.1Ge0.1Sb0.9S4 electrolyte, which released low amounts of H2S under ambient conditions, demonstrated the ionic conductivity of 5.1 × 10−3 S/cm at normal atmospheric temperature and the conducting activation energy of 0.156 eV. The enhanced ionic conductivity was attributed to the improvement of crystallinity and the unit cell enlargement caused by interstitial sodium defects.

(Digital Presentation) Synthesis and Properties of Llithium Iron Phosphate Cathode Materials without Carbon Coating with High-Rate Property

Lithium iron (ferrium) phosphate (LFP) use iron as a transition metal, so there is lower resource risk. And because of tolerant to overcharging, they have excellent safety and durability. Lithium-ion secondary batteries using LFP have become widely used as main power sources for EVs and ESSs in recent years. Originally, LFP has higher bulk resistance than other layered rock salt-based positive materials, so that carbon-coating was applied to surface of LFP particles. This idea was extremely effective in putting LFP into practical use. However, the use of the carbon coat has led disadvantage of high cost despite the use of cheaper iron because the manufacturing process increases. We report that we have developed LFP that has extremely high-rate charge and discharge performance even though it does not have carbon coating. Figure 1

(Invited) Electrochemical Pathways Towards Recycling Spent Lithium-Ion Batteries

The ever-increasing grid-scale energy storage farms and electric vehicles call for more secondary lithium-ion batteries (LIBs). However, the battery resource is limited. Thus, the retired LIB is a potential secondary resource for remaking LIBs. Thus, it is urgent to develop efficient and green methods to recycle spent LIBs. Based on the long-time establishments in high-temperature molten salt and electrochemistry, the author developed electrochemical ways to repurpose spent LIBs, including molten salt electrolysis, cathodic assisted electrolysis, and paired electrolysis approaches. Unlike traditional way using chemicals to break down the chemical bonds, the electrochemical methods use electrons to enable the separation. As such, the electrochemical ways are green if renewable electricity is integrated. Hence, we hope to employ electrochemical technologies and classical thermodynamic principles to develop green recycling methods, aiming to provide fundamental insights into the sustainable battery development and renewable energy utilization.

Effect of Heteroatoms Doped Nanoporous Carbon for Aqueous Zinc–Bromine Battery

As interest in renewable energy increases, the importance of batteries that store surplus power is also increasing. However, frequent ignition issues with the lithium-ion secondary battery arose. One of the next-generation batteries, Zinc-Bromine based aqueous flow batteries, are being actively studied based on advantages of high safety and environmental benignity. However, there is an exorbitant price for flow battery due to the use of a membrane, an electrolyte tank, and a pump. In order to eliminate the shortcomings, this research introduced a form of membraneless and flowless systems.In this study, a nanoporous carbon material doped with nitrogen and boron heteroatoms was synthesized and coated on graphite felt. Differences in electrochemical performance were observed when carbon was coated with different slurry compositions (activated carbon: conductive carbon: binder), dopant amount of heteroatoms, and carbon loading mass. Cyclic voltammetry was performed with a three-electrode system to observe the faradaic reaction of active materials according to the potential change. Besides the difference in contact angle for ZnBr2 electrolyte, there are differences in single cell test at 20 mA/cm2 & 2 mAh/cm2 and performance test at 20 mA/cm2 & 24.3 mAh/cm2. These causes can be explained not only by the effect of the different slurry compositions, but also by the interaction of the active material with the coated carbon. Also, the redox reactions of bromine anion during charging process could be a clue for the battery capacity. Cathodic reactions for polybromide [Br2 + Brn – → Brn+2 – , (n=1,3,5...)] can be analyzed by Raman spectroscopy. The peak shift and deconvolution of the Raman data can measure the progress of cathodic reactions. The boron dopants can stabilize the reversibility of faradaic reactions and induce high resistance to strong acid electrolytes (For ZnBr2 electrolyte of 2.0 M or higher, it has a value under the pH 4). Figure 1