Last developments in polymers for wearable energy storage devices

International Journal of Energy ResearchEarly View REVIEW PAPEROpen Access Last developments in polymers for wearable energy storage devices Silvia Lage-Rivera, Silvia Lage-Rivera orcid.org/0000-0003-3889-3847 Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, SpainSearch for more papers by this authorAna Ares-Pernas, Ana Ares-Pernas Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, SpainSearch for more papers by this authorMaría-José Abad, Corresponding Author María-José Abad maria.jose.abad@udc.es Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, Spain Correspondence María-José Abad, Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol 15403, Spain. Email: maria.jose.abad@udc.esSearch for more papers by this author Silvia Lage-Rivera, Silvia Lage-Rivera orcid.org/0000-0003-3889-3847 Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, SpainSearch for more papers by this authorAna Ares-Pernas, Ana Ares-Pernas Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, SpainSearch for more papers by this authorMaría-José Abad, Corresponding Author María-José Abad maria.jose.abad@udc.es Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol, Spain Correspondence María-José Abad, Universidade da Coruña, Campus Industrial de Ferrol, Grupo de Polímeros-CIT, Campus de Esteiro, Ferrol 15403, Spain. Email: maria.jose.abad@udc.esSearch for more papers by this author First published: 08 April 2022 https://doi.org/10.1002/er.7934 Funding information: Xunta de Galicia, Grant/Award Numbers: ED431C, PID2020-116976RB-I00 AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Summary Our modern and technological society requests enhanced energy storage devices to tackle the current necessities. In addition, wearable electronic devices are being demanding because they offer many facilities to the person wearing it. In this manuscript, a historical review is made about the available energy storage devices focusing on super-capacitors and lithium-ion batteries, since they currently are the most present in the industry, and the possible polymeric materials suitable on wearable energy storage devices. Polymers are a suitable option because they not only possess remarkable mechanical resistance, flexibility, long life-times, easy manufacturing techniques and low cost in addition to they can be environmentally friendly, nontoxic, and even biodegradable too. Moreover, the electrical and electrochemical polymer properties can be tunning with suitable fillers giving to versatile conducting polymer composites with a good cost and properties' ratio. Although the advances are promising, there are still many drawbacks that need to be overcome. Future research should focus on improving both the performance of materials and their processability on an industrial scale, where additive manufacturing offers many possibilities. The sustainability of new energy storage devices should not be forgotten, encouraging the use of more environmentally friendly materials and manufacturing processes. Abbreviations 1D one dimension 3D three dimensions A area of the electrode applied AM additive manufacturing C capacitance CB carbon black CF carbon fibers CFO cobalt ferrite CNF carbon nano fibers CNT carbon nano tubes CPC conductive polymer composites D dielectric displacement d thickness of dielectric layer DEA dielectric thermal analysis DLP digital light processing E applied electric field Eb breakdown strength EBM electron beam melting ECNF electrospun carbon nanofibers EDLC electrochemical double layer capacitor EH energy harvesting F Farad FDM fusion deposition modelling GN graphene nanosheets GO graphene oxide HN-CNF N-doped carbon nanofibers ICP intrinsically conducting polymers IoT internet of things LDM liquid deposition modeling LFP lithium iron phosphate LIB lithium-ion batteries LMO lithium manganese oxide LTO lithium titanate oxide MABs metal-air batteries MWCNT multi-walled carbon nanotubes PANI polyaniline PDA polydopamine PEDOT:PSS poly(3,4-ethylenedioxythiophene) polystyrene sulfonate PEG poly ethylene glycol PEO polyethylene glycol PET poly ethylene terephthalate PHBV poly(hydroxy butyrate-co-hydroxyvalerate) PI polyimide PLA poly lactic acid PMMA poly methyl methacrylate PPY polypyrrole PTPA poly tri-phenyl amine PVA polyvinyl acetate PVDF poly vinylidene fluoride PVDF-HFP poly (vinylidene fluoride)-co-hexafluoropropylene PVP poly vinyl pyrrolidone PZT lead zirconate titanate QD quantum dots RF radiofrequency rGO reduced graphene oxide SC super-capacitors SLA stereolithography SLS selective laser sintering SWCNT single walled carbon nano tubes t discharge time TRGO thermally reduced graphene oxide T-ZnOw tetra-pod zinc whiskers Ue energy density ε0 dielectric permittivity of vacuum (8854 × 10−15 F cm−1) εr dielectric permittivity 1 INTRODUCTION OF ENERGY STORAGE DEVICES AND POLYMER COMPOSITES IMPLEMENTATION IN THEIR MANUFACTURE 1.1 The need of energy storage devices Over the last few decades, humanity is going through a technological change for the sake of reaching the information era, in which more and more electronic devices are needed. In addition, the industry 4.0 is attempting to make factories more intelligent by introducing all their machines and processes interconnected, which requires a considerable number of electronic devices connected by internet of things (IoT). Some of these electronics are being increasingly demanded by ordinary people,1 who take them as wearable electronics2 and sensors.3-5 Textile industry is already designing fashionable electronic devices that can be worn as accessories (smart watches, necklaces, earrings, etc.) and clothes.6 For example, Li et al7 reported a wearable and flexible pressure sensor, very useful in health care monitoring. This kind of portable devices need flexible and lightweight materials. Some of them require low power incoming (0.1-10 mW) and thus they can be fed with energy harvesting (EH) devices.8-10 EH (Figure 1) is a clean energy obtaining method which uses wasted energy that is free in the environment. However, the electrical power harvested through these technologies has interruptions in their generation so, in most applications, it is desirable to couple an energy storage unit compatible with the device. Energy production and storage can be achieved thanks to multifunctional materials, which are able to develop various tasks (energy storage and harvesting) in an efficient way.11, 12 FIGURE 1Open in figure viewerPowerPoint Energy harvesting Taking a historical review, electronic devices have been powered by rechargeable batteries since Gaston Planté invented the first one based on acid and lead in 185913 (Figure 2A). This technology faces several disadvantages such as their limited lifetime caused by the heating up and down that the battery suffers when the ions flow back and forward, or the environmental contamination because of their chemical components in the cathode and anode. Scientists are trying to overcome with these difficulties hence, new studies are appearing looking for materials with high power and energy density properties as an alternative to common batteries. In 1878, Maiche discovered the metal-air batteries (MABs),14 which seemed like a good lead-acid alternative. MABs are composed of an air-breathing cathode (which catches oxygen from the air), a metal anode (zinc,15 lithium,16 sodium, potassium, and more) and an electrolyte, which can be aqueous or nonaqueous. MABs can be assembled in several forms (solid-state,17 fiber-type,18 etc) to cover a wide range of applications. Despite the great advantages of MABs, such as their remarkable density (3-30 times higher than lithium-ion batteries [LIB]) or high level of safety, they face several disadvantages as their lack of scalability for industrial development, and the need of more suitable and enhanced materials compose them.18, 19 However, scientists are trying to overcome these drawbacks20 and hopefully MABs will be present in our future electronic devices. Nowadays, the storage devices that are most available in the industry are super-capacitors (SC) and LIB because of their mechanical robustness and electrochemical sustainability21 so, this review is focused those two technologies. FIGURE 2Open in figure viewerPowerPoint Schemes of (A) lead acid battery (B) SC (C) SC technologies and principal materials (D) LIB (E) LIB cathodes materials. LIB, lithium-ion batteries; SC, super-capacitors The use of polymers and polymer composites in the fabrication of energy storage devices has been investigated21 because of its multiple advantages over inorganic materials. A polymer material is obtained by a polymerization process, in which a lot of molecules (called monomers) are linked to each other by covalent bonds. They seem a good alternative to the typical inorganic ones used so far in energy storage devices because of their intrinsically physical properties.22 They are flexible, resistant, tailorable, lightweight, easy to process, and they have lower cost than inorganic ones. Polymers possess some intrinsic physical properties (viscoelasticity, glass transition temperature, etc.) which make them unique and very useful in several applications. Moreover, the use of bio-based polymers23, 24 can help with the current ecological challenges. Biopolymers are obtained from natural sources, they are non-oil dependent, nontoxic, they help with the current ecological challenges, and they are biodegradable under certain conditions, which make them discard easily. For the manufacture of energy storage devices, polymeric materials must have certain electrical properties. The most commonly used are intrinsically conducting polymers (ICP), generally with poor mechanical properties, and conductive polymer composites, where an electrical insulant matrix is added with conductive fillers. These synergistic combinations allow optimization of both mechanical and electrical properties, impossible to achieve from each component alone. The main target of this comprehensive review is to explain the principal energy storage devices industrially available and review the advances in the design and performance of these energy storage devices obtained using ICP and conducting polymer composites. Therefore, it is going to focus on new developments for wearable LIB and SC, where the implementation of polymeric materials is essential to achieve the desired properties. 1.2 Super-capacitors The most studied alternative to lead-acid batteries has been SC, discovered in 1957 by General Electric's H.I. Becker.13 SC are a kind of capacitors with a high capacitance, which makes SC able to store energy. In these devices, the energy is stored electrostatically within the carbon pores at the electrodes surface area, so the capacitance and consequently the energy density increase with the controlled porosity.25 This results in the increase of speed in charge and discharge cycles (1-10 seconds26) but it also produces a reduction in their lifetime. However, SC possess a high lifetime because they do not need chemical reactions to store the energy (around 105 charge/discharge cycles27). SC are mainly composed by two identical electrodes acting as anode and cathode based on porous materials, normally carbonaceous (activated carbon, graphite,28 ICP and others), on account of their high capacitances (up to 394 F g−1)29 and large surface areas. They also possess an active layer, a separator for avoiding short-circuits between the anode and cathode, and the current collectors (Figure 2B). Unlike capacitors, which are composed by two plates with a dielectric inside as an insulator, SC have an electrolyte as insulated active layer. Therefore, the distance between their plates can be significantly smaller than in capacitors. The electrolyte is usually liquid, made by metal salt solution with organic or aqueous materials as solvent. Some investigations propose to use dielectric polymers as SC electrolytes because they avoid the need of a separately separator.12, 30 There are three types of SC; electrochemical double layer capacitor (EDLC), pseudo-capacitors, and hybrid capacitors, Figure 2C summarizes the most used materials in each one. The charge storage mechanism and the electrodes capacitance change in each of them: EDLCs were the first SC discovered when Standard Oil Co. (1966) was doing experiments with porous carbon material as electrodes, and they realized that the energy was stored in the carbon pores. They are mostly made with carbonaceous materials due to their high specific surface area, which electrostatically store the charge at the interface between the electrode and the electrolyte.31 EDLC can be easily disposable and burnable avoiding high costs in their discarding and recycling. Nowadays, they are still the most used ones due to their technical development. EDLC main problems are their low energy density due to their low capacity. Muralee Gopi et al26 proposed to use surface modification methods (N- and S-doping, surface exfoliation, and surface activation) to overcome these drawbacks. From another point of view, Liu et al32 focused their study on ways to avoid SC self-discharge to improve SC technology. This improvement can be obtained by tuning the separator, making modifications on the electrodes, or modulating the electrolyte. Pseudo-capacitors do not store the charge electrostatically but electrochemically with reversible surface (or near-surface) Faradaic redox reactions, this means the involving of charge transfer reactions throughout the electrochemical interface. They owe their name to their kinetic and thermodynamic behavior which can be explained with the mathematical model for surface adsorption and desorption.33 Their electrodes could be made with transition metal oxides or conducting polymers.31, 34 Despite their lower specific power density and stability in comparison with EDLC, their specific capacitance is high. However, pseudo-capacitors lose capacity faster than EDLC do because of the electrostatic stresses that they suffer in charge and discharge processes. The Hybrid SC are composed by a combination of EDLC and pseudo-capacitor leading to high energy densities and high capacitances.26 New developments are appearing in the hybrid SC field as lithium-ion capacitors,35 which possess high power and energy density. Compared to current batteries, SC do not suffer from explosion, so they gain on security. Moreover, they do not need toxic chemical materials to work, making them environmental-friendly and easy to recycle. Besides, SC are smaller than lead acid batteries and they can be charged and discharge thousands of times very quickly, as a result, new applications arise. The Ragone plot36 (Figure 3) summarizes the energy and power densities of the different energy storage devices. Despite current SC do not possess high energy density, they have the highest power densities making them suitable in current stabilization applications (variable voltage). That is the reason why SC are very used in electronic (power supply circuits, computers, inverters, cameras, etc.), energy production (wind and solar energy), and transportation devices. Moreover, scientists are attempting to enhance SC' energy densities improving the electrodes performance by adding novel 2D material such as MXenes,25 metal-organic frameworks37 or by functionalization with thiol.38 FIGURE 3Open in figure viewerPowerPoint Ragone plot In addition, SC are now an essential component in the development of renewable energy devices because they can support intermittent input energy. Also, the electrical vehicle industry has an eye on this technology on account of their short charge rates, long lifetime, and small volume making them suitable for fast recharging vehicles used in short-frequent trips.39 Several researchers have recently published advances in SC technology for vehicle applications,40, 41 some of them combine super capacitors with other batteries gaining better performances.42-45 SC are also being used in wearable and portable energy storage devices.46-48 The investigation reported in this field always attempt to enhance the energy density, flexibility, and tailorability. Polymer-based materials can provide these properties.49 Wang et al50 recently stated last advances in polymer materials for electrodes and electrolytes in SC which can be used in wearable applications. 1.3 Lithium-ion batteries During the oil crisis in 1970 decade, Stanley Whittingham (2019 Nobel Prize) discovered LIB thanks to some experiments consisting of holding lithium ions between titanium sulfite plates. Although, he did not pay much more attention to the technology and it was not until 1991 that Sony and Ashai Kasei developed the first commercial LIB.13 The most outstanding LIB' characteristic is their energy density because they exceed the values of both Lead-Acid batteries and SC. Regarding the efficiency, LIB can achieve a 92% vs the 60% of traditional batteries, considering the efficiency as the rate charge/discharge density. The last remarkable advantage of LIB is their security. LIB do not explode because they have control systems to protect them from overcharges. By contrast, the cost of LIB is higher than Lead-Acid ones, but this parameter is decreasing in recent years. The main parts of LIB are the cathode, anode, electrolyte, separator, and current collectors (Figure 2D). Energy storage occurs by some electrochemical redox reactions between the anode and the cathode electrodes composed by a range of electrochemically active materials. Traditional LIB has a Lithium cathode, due to its high electrochemical capacity and a carbonaceous material anode (activated carbon, carbon black, graphene, etc.).51 Figure 2E collects possible LIB cathode materials,52 all of them contain lithium. This material possesses a high reactivity (even with the water) so, there is no need of complex chemicals as electrolyte. The aforementioned reactivity also allows them to store a lot of energy in its atomic bonds, resulting in higher energy density in a lower volume.53 The most common LIB' anodes are the graphite oxide ones because they support very well the volume changes that LIB suffer. However, graphite anodes have low capacities (372 mAh g−1) and their rates of performance (capacity over number of cycles) are poor so new materials are being investigated to replace them.54 Other carbonaceous materials (carbon nano fibers [CNF], carbon composites, biomass carbon, mesoporous carbon, etc.) are a suitable option because they help the lithium diffusivity and electrons movement between electrode and electrolyte. Another anode material could be the silicon, because of its high theoretical specific capacity, low cost, and abundance in nature.55 However, silicon has issues supporting the volume changes that the cell suffers. The main purpose of the electrolyte is allowing the correct movement of lithium ions while the separator prevents short-circuit. However, the motion of ions carries degradation problems on the separator and the electrolyte so, new alternatives to traditional electrolytes are needed.56 Chen et al57 have recently noted the last progresses of solid-state electrolytes which reduce the degradation issue. From a different angle, some studies are focused on polymer composite electrolytes58, 59 because they avoid the need of the separator. LIB is mainly used in portable electronics, such as smartphones, due to their high energy density (see Ragone plot in Figure 3), but they are also used in vehicle and industrial applications.37 They can even be used for ultrafast charging and discharging applications. Nevertheless, traditional LIB shows difficulties in wearable devices due to their lack of flexibility and adaptability to the human body because of their rigid plates as energy collector, currently made with copper and aluminum. To overcome this drawback, scientists are looking for new flexible and adaptable materials with enough electrochemical response to be used in LIB fabrication.60 To achieve this goal, researchers have used polymer composites,56, 61 always searching for competitive electrical conductivities, electrochemical properties, and high mechanical strengths. Their work focuses on using a polymer or a polymer composite as electrode and then adding the anode/cathode substances, the most used ones are lithium titanate oxide (LTO)/lithium iron phosphate (LFP) and LTO/lithium manganese oxide (LMO). Once the electrodes are ready it is only necessary to add the electrolyte to get the LIB. Another field for LIB improvement is the study of new electrolyte materials because new requirements on their properties are needed like being environmentally-friendly and low-cost. Focusing on the physical properties, they must possess a high ionic conductivity, wide potential window, high thermal, chemical, and electrochemical stability, and be inert to the other LIB parts. In both SC and LIB electrodes is important not only the nature of their materials but also its microstructure. The most common structures in energy storage devices can be obtained by three methods, mixing type, core-branch and core-shell (Figure 4). Zhu et al63 reported in 2015 the electrodes microstructure design and they confirmed the advantages of two materials composed electrodes. FIGURE 4Open in figure viewerPowerPoint Main structure solutions of wearable batteries (Reference: 62. Reproduced with permission. Copyright 2015, Wiley-VCH) Researchers are also worried about LIB security because the portable devices are really close to the human body. Chen et al64 recently reviewed the most important investigations about the electrical, thermal,65 and mechanical issues in LIB. Once these safety concerns are solved, new applications for LIB will appear. Table 1 compares the principal energy storage properties of lead-acid batteries, SC and LIB in order to see the strengths of each technology. There are also data of the newest and improved technologies. TABLE 1. Comparison of the principal properties between the different energy storage technologies Energy storage technology Energy density (W h kg−1) Power density (W kg−1) Cycling stability References Lead-acid battery 25-35 150 50-100 66 Super-capacitors (SC) 100-150 10 000 >30 000 26, 32 SC (graphene oxide scrolls) 206 32 000 >20 000 38 Lithium-ion batteries 100-250 500-2000 >500 26, 33, 55 Li-S 2600 — — 67 1.4 Required physical properties on the polymer composites for energy storage To improve the performance of batteries, the research is focused on increasing the specific physical properties of the polymer composites from which they are made. The main parameters required for studying and comparing electrochemical cell performance are both energy and power densities. The energy density is the amount of charge that a battery can store whereas the power density is the quantity of energy that the battery can discharge, both parameters regarding its mass. A battery with high energy density provides energy in a lower volume, which means reducing its cost and footprint. In addition, a battery with high power-deliver capability is suitable in applications where high power peaks are required. The maximum volumetric energy density depends on the applied electric field as it is shown in Equation (1). Simultaneously, Equation (2) collects the relation between the dielectric displacement in linear dielectrics and the applied field. Solving the Equations (1) and (2), Equation (3) shows the maximum energy density that a linear dielectric material can store. Therefore, it depends on the dielectric parameters of the material because it is related to the relative dielectric permittivity and to the dielectric breakdown strength.68 U e = ∫ 0 D m E dD . $$ {U}_e={\int}_0^{D_m}E\ dD. $$ (1) D = ε 0 ∙ ε r ∙ E . $$ D={\varepsilon}_0\bullet {\varepsilon}_r\bullet E. $$ (2) U e = ∫ 0 D m D ε 0 ∙ ε r dD = 1 2 ∙ ε r ∙ ε 0 ∙ E b 2 . $$ {U}_e={\int}_0^{D_m}\frac{D}{\varepsilon_0\bullet {\varepsilon}_r} dD=\frac{1}{2}\bullet {\varepsilon}_r\bullet {\varepsilon}_0\bullet {E_b}^2. $$ (3)The dielectric breakdown strength is the most extreme electrical potential that a material can oppose before the electrical flow gets through the material. Both electric breakdown and dielectric permittivity can be easily measured in a laboratory.68 Polymer dielectric permittivity69 can be measured either directly with a DEA machine or by measuring the material capacitance, as shown in Equation (4). ε r = C ∙ d ε 0 ∙ A . $$ {\varepsilon}_r=\frac{C\bullet d}{\varepsilon_0\bullet A}. $$ (4)Last, the power density relation with energy density is shown on Equation (5). P m = U e t . $$ {P}_m=\frac{U_e}{t}. $$ (5)Furthermore, parameters as the cycle life, charge/discharge characteristics, mechanical resistance, durability or degradation against external agents (like water, soaps or ultraviolet radiation) are measured to evaluate the future performance of the energy storage device.50, 70 Currently, there is a lack of high-performance polymeric electrode and electrolyte materials so new studies are emerging.67, 71, 72 Polymer composites are very often used in energy storage applications due their high dielectric permittivity and high dielectric breakdown strength.30 However, there are some important factors such as the material additives, morphology, internal defects, and chemical impurities which affect the dielectric properties. 2 POLYMER AND POLYMER COMPOSITES FOR BATTERIES OBTAINING AND THEIR VIABILITY FOR WEARABLE DEVICES 2.1 Manufacturing methods of obtaining polymer-based batteries: additive manufacturing and electrospinning The manufacture of more sustainable, efficient, and cheaper batteries is a key point in the development of greener energy technologies. One industrial scalable non-waste method very promising for battery obtaining is additive manufacturing (AM),73 also known as 3D printing, due to their suitable characteristics like more freedom in design and low-cost feed materials. This method creates physical prototypes from virtual models in an easy process adding materials layer-by-layer. Nowadays, AM is being used in several fields such as bioscience, electronics, and energy storage74 obtaining devices topologically optimized. Furthermore, AM technologies are becoming more affordable and accessible. There are several AM processes, each of one is suitable for a different feed material and for different final applications (fusion deposition modelling [FDM], stereolithography [SLA], liquid deposition modeling [LDM], selective laser sintering, electron beam melting). However, the most used ones in energy storage devices are Fused Deposition Modeling and Liquid Deposition Modeling due to their scalability and their easy design method.75 Both FDM and LDM are capable of printing macro- or micro- (even nano-) structures so different ones (fiber, cable, mesh, etc.) can be obtained.76 An alternative to AM technologies is electrospinning (Figure 5C), a widely used technique which obtains ultrafine polymer fibers with nano-sized diameters.77 Electrospinning obtains nanofibers trough the coaxial stretching of a viscoelastic solution by applying a high voltage.78 They possess a high area/mass ratio so they fit in energy storage devices as electrodes due to their ease in charge conduction mechanism.61 FIGURE 5Open in figure viewerPowerPoint Manufacturing methods of obtaining polymer composites (A) liquid deposition modelling printing process (B) fusion deposition modeling printing process (C) electrospinning process Following, the principal AM and electrospinning obtaining methods for batteries are explaining with some published investigations as examples. Table 2 collects capacity and electrical conductivity data of these studies to compare their electrical performance. TABLE 2. Different examples of materials obtained by several manufacturing methods and their electrochemical properties Materials Composition Flexible Obtaining Method Capacitance (F g−1) Conductivity (S cm−1) Uses References P(VDF-TrFE-CFE) 8:1:1 Yes LDM — — Binder 79 PVDF-HFP No LDM — 3.8 × 10−3 Battery separator 80 Commercial graphite slurry No LDM 1.3 × 102 — Electrodes for LIB 81 Graphite/LiNi0.6Co0.2Mn0.2O2 Several Yes LDM (0.6-1.2) × 10−2 (5-9) Wearable LIB 82 (LFP/PLA)/(SiO2/PLA) 6:4 No FDM 1.11 × 10−3 3.96 × 10−5 Electrodes for LIB 83 Li2TP/CB/PLA/PEGDME500 4:4:1:1 No FDM 84 PEO/LiTFSI 20:1 No FDM — 3.79 × 10−6 Electrolyte for LIB 72 Graphene+active materials/PLA 4:6 No FDM — — Electrodes for SC and LIB 85 EGPEA/PA