**5.1 Metal composites based ionic polymer on microcellular foamed Nafion**

The energy harvesting experimentation of the IPMC composite membrane was lead in the 20 Hz frequency or less. When vibrations of a definite frequency window were allowed, the microcellular foamed samples were permitted, and a prominent proportion of energy was gathered from foamed samples compared to non-foamed samples. The outcome value was transformed by computing the modification data attained by the standardisation for the obtained current. In the band of frequency, the subsequent data was transformed into the value of root mean square (RMS), and also a 20 s time from the entire 30 min time approximately delineated the higher data was designated and connived. Two polymer membrane matrices were investigated in similar analysis environments, and the average value was accepted. For every analysis scenario, we connived a graphical output of current versus time. That was corroborated by that foamed IPMC samples logged a band of high frequency with the higher value. Moreover, in the band of lowfrequency, it is depicted that the IPMC samples of non-foamed higher energy harvest compared to the foamed system. This analysis is accredited to the much critical non-foamed samples movements. In the band of frequency about 10 Hz, it was investigated that the foamed system deviate much higher swiftly than the

*IPMC Based Flexible Platform: A Boon to the Alternative Energy Solution DOI: http://dx.doi.org/10.5772/intechopen.99434*

**Figure 8.**

*Water content, capacitance, and output current versus frequency variations according to the foaming ratio of IPMC specimen [55].*

specimen of non-foamed; also, the following data fluctuated up to roughly three times. The capacitance was calculated with the 0.001 μF resonance in the 120 Hz band after drying in a vacuum under all conditions of the specimen. Distinct outputs were gathered for every analysed system. As the ratio of foaming incremented, the retention capacity of cells' water was enhanced thereafter, along the capacitance was also incremented. It is presumed that the thickness increment in the membrane of polymer electrolyte and enhancement of water retentivity ameliorate the effective enactment of the capacitance. These are for the containing of water in the IPMC matrix and affecting the responses as a relaxation factor depicts the prominence outcome of the capacitance [55]. The obtained yields are delineated in **Figure 8**.

## **5.2 Ionic polymer-metal composite based water electrolysis for solar energy storage**

The typical gas generation rate was calculated using the total volume of hydrogen gas composed divided by the duration of the 300 s. When the applied voltage increases, the gas generation rate enhances for all three IPMCs. Fascinatingly, the etched IPMC delineates a steeper increase compared to both the sanded and control IPMCs. Even though sanded and etched IPMC have higher whole gas production rates than the control IPMC, the sanded IPMC's gas generation rate was higher at a lower voltage, whereas the etched IPMC's gas generation rate was higher the higher voltage. To calculate the efficacy of the different fabrication process, the average gas production rate, the average voltage supplied, and the average current through the IPMC was computed to regulate the system's competence. From the graph, all three IPMC exhibits higher efficiency at lower voltage and their efficiency decrement at a variable rate as the voltage applied increases. Sanded IPMC has the highest efficiency and highest gas generation rate around 3 V, successfully producing that increasing the surface area through sanding will advance the performance of IPMC for energy harvesting. Although etching has a higher gas generation rate compared to the control, it must be noted that its energy efficiency values are often lower compared to both the sanded and control IPMC. On the other hand, at lower supply voltages, the electrolysers at higher temperatures were lagging in the generation of gas. However, the gas generation rate was higher at higher applied voltages, signifying a higher average slope in applied voltage vs. gas generation rate. The proficiency of the IPMC electrolyser generally decreases as the voltage applied increases. However, for higher temperatures (45°C, 55°C and 65°C), an increase in the productivity of the IPMC generator is seen as the voltage applied surges from 4 V to 5 V. When the temperature is low (45°C), it behaves similarly to IPMC at

#### **Figure 9.**

*Comparison illustration of IPMC H2 production rate and IPMC electrolyser's efficiency under temperatures variation [56].*

room temperature, however, when the temperature increases to 45°C, the electrolyser seems to hold a constant efficiency. As the temperature increases to 65° C, the efficiency seems to progress with increased voltage [56]. Comparison analysis illustrated in **Figure 9**.

#### **5.3 Nafion-PVA composite membranes performance for direct methanol fuel cells**

This research analysis has been targeted to investigate the permeability of methanol and fuel cell proficiency of Nafion-PVA composite membranes in the functionalities of the thickness in the range of 19 97 μm. Also, the composite polymer membranes were fabricated by the Nafion polymer that is placed in the nanofibres of (PVA) polyvinyl alcohol. The methanol infusion resistance of the Nafion/PVA composite membranes exhibits a linear deviation versus thickness. The variation between actual and apparent permeability leads to a calculated data of 4.0 <sup>10</sup>–7 cm2 s <sup>1</sup> for the proper or intrinsic permeability in the phase-in bulk of the membranes in the composite matrix. The integration of nanofibers of PVA creates a noticeable decrease of one order scale in the permeability of methanol associated with Nafion original membranes. The proficiency of DMFC of the electrode membrane assemblages fabricated from pristine and Nafion-PVA membranes was analysed at 95°C, 70°C and, 45°C in different concentrations of methanol, like as 3, 2 or 1 M. The membranes polymer composite in nanoscale with the thicknesses of 47 μm and 19 μm corroborated densities of power of 184 mWcm<sup>2</sup> and 211 mWcm<sup>2</sup> in the temperature of 95°C and the concentration of 2 M methanol. It is analogous to the finding for membranes by Nafion with an analogous thickness of the similar conditions, 204 mW cm<sup>2</sup> and 210 mW cm<sup>2</sup> , correspondingly. However, a higher degree of utilisation of Nafion work as a material of protonconductive in Nafion-PVA membranes is delineated for the lesser proportion of Nafion polymer in the membranes composite. Therefore, substantial reserves in the *IPMC Based Flexible Platform: A Boon to the Alternative Energy Solution DOI: http://dx.doi.org/10.5772/intechopen.99434*

expended Nafion amount are significantly achievable. Moreover, the PVA nanofibers incorporation in the time of fabrication exhibited the polymer membranes with lower thickness with higher mechanical attributes; however, the modification of membranes of pristine Nafion become unviable below the 50 μm thickness. The innovative membranes of nanocomposite are fabricated using Nafion polymer amalgamated in between the functionalised nanofibers of polyvinyl alcohol (PVA) and investigated the attribution of DMFC performance and methanol permeability. Furthermore, methanol's primary permeability is detected from the attribution of original permeability inherent to the material of the membrane matrix. The composite polymer membranes delineated the permeability coefficient of methanol with a magnitude reduction of one order compared to the pristine membrane of Nafion for the barrier effect triggered with the nanofibers. Furthermore, the nanofiber phase is not impacted in the coefficient of electro-osmotic drag of methanol; in some definite circumstances, the low values were detected in membranes of Nafion-PVA. Fascinatingly, the coefficient of electro-osmotic drag of methanol was decremented corresponding to temperature as an alternative of the water responses conveyed to increment with temperature increase. Direct methanol fuel cell analyses at variational methanol concentration and temperature conditions delineated the extreme outcomes to be attained in 2 M solutions at 95°C. In these scenarios, the membranes of Nafion-PVA of 47 and 19 μm of thickness attained comparable engagements to Nafion membranes with equivalent thickness compared to the high protonic resistance detected at the membranes polymer composite. Introducing a phase of nanofiber in the Nafion polymer matrix and the thin membranes use leading to important reserves in the expended Nafion polymer amount can be proficiently managed to keep higher performances [57].

#### **5.4 Ocean-based energy production system using the electrochemical alteration of wave energy with the help of ionic polymer-metal composites**

In this research work, ionic polymer with metal composites (IPMCs) based on an energy harvesting platform stored the kinetic energy from the waves of the ocean and transformed it into electricity. However, the investigational analysis depicted that IPMC composite materials attribute several benefits, like durability and softness; they also counter speedily to wave parameters like wavelength, amplitude, and frequency. Moreover, the data analysis recorded for 296-day delineated that the gross power density engendered persisted stability around 245 μW/m2 . The decaying electrical performance of IPMC polymer matrix in a span of long term process is trivial. Generally, the modules rotation is nominal: the 18 modules' gross amplitude in the motions of rolling, pitching, and yawing is roughly 1 degree in the 0.48 Hz frequency.

Furthermore, the displacement in the z-direction is profoundly high compared to the incident waves' amplitude and different displacements directions. The investigational outcomes demonstrated the gross power density intensely oscillated at a particular time in a day more than 180 μW/m<sup>2</sup> , also with the power density average of roughly 245 μW/m<sup>2</sup> and 292 μW/m2 peak value. The IPMC polymer system's power density is mostly smaller than the conventional energy resources; furthermore, the IPMC system is economical and sturdy. The system power can be enhanced by accumulating the effective area of the IPMC membrane matrix. On the other hand, several explorations will emphasise evaluating buoy systems in fluctuating wave and current presences to analyse the configuration system stability in the ocean at the time of extreme weather or typhoon. Those studies will assist in augmenting the long-term performance and lessening the prices of maintenance at

the installation time. Furthermore, the IPMC material bending plays a potential role to develop the proficiency of the energy harvesting structure [58].

#### **5.5 Water and ion transportation in Perfluorosulfonated ionomer membranes for application of fuel cells**

The volume fraction of water θ rises with lessening equivalent (EW) weight values of the IPMC membrane, irrespective of the membranes types and the counter cations. That point denotes the water present in the membranes matrix escalates with the concentration surges of the group of ion exchange. Afterwards, the water molecule presents in the groups of sulfonic acid and the counter cations within membranes to create the regions of the ionic cluster. On the other hand, anticipated that the membranes possess lesser EW values help to advance more numerous and much extensive ionic cluster zones in the membrane by providing high ionic conductivity. However, for the variation of cations species, the content of water order is Na<sup>+</sup> < H+ < Li<sup>+</sup> for all the matrix of membranes. It designates that the content of water relies on the species of cations, and specifically, Li + cations can fetch the molecules of water for having the higher hydrophilic features. The ion-exchange group contributes to the formation regions of the ionic cluster. The total water molecules number in the membrane per ion-exchange group is *λ* also enhances with lessening the equivalent weight value; also, the order of *λ* for cations species variation is similar with the volume fraction of water Na<sup>+</sup> < H+ < Li<sup>+</sup> . It is advised that the number and size of regions of a cluster of ions in the matrix of membranes are pressurising with the value of the equivalent weight and the cations species variation. This signifies that when the equivalent weight diminishes, the counter cations and groups of sulfonic acid attract much water in the ionic ambience. The content of water is calculated by the stability in between the force of osmotic hydration in the ion and elastic force cluster persuaded with the fluorinated polymer deformation that is the leading chain. The activity of water can be equally presumed in the membrane matrix and the outer side of the solution of the membrane.31 If the number and size of the cluster region of ions enhance by escalating the membrane volume, the membranes density will be diminished for the water thickness (ca. at 25°C 1 g cm-3,) is lesser than the membranes itself (at 25°C around 2 g cm-3). The membrane densities reduce with reducing the equivalent weight value, particularly the Li-form membranes thicknesses that are lesser than the different cations-form membranes.

Furthermore, the membrane possesses a lesser equivalent weight value that enlarges the volume, and the cluster regions of ion are primarily developed mostly, specifically in the membrane of Li-form. The membrane possesses a lesser equivalent weight value that can create greater expanded cluster regions of ions despite the cations'species. The membranes' ionic conductivity is roughly correlated with the number and the size of cluster regions of ions in the matrix of membranes. Furthermore, the conductivity of all protonic membranes is significantly greater than the rest of the membranes of cationic form. It is usually attributed that the proton of the aqueous solution is elated with the help of the hopping process and can be transported faster compared to the rest of the cationic species transferred using the vehicle process. The probable aspects of finding out the conductivity are the mobility and concentration of carrier cations within the matrix of membranes that is calculated from the outcomes of the density of membrane and conductivity of ions. The sulfonic acid group concentration within the membranes, i.e. *C*SO3- is analysed and equivalent to the carrier cations attention. However, the carrier cations concentration for all membranes is impervious to the equivalent weight value of membranes. The carrier cations species mobility is enhanced with reducing the

#### *IPMC Based Flexible Platform: A Boon to the Alternative Energy Solution DOI: http://dx.doi.org/10.5772/intechopen.99434*

EW value. Like this, the increment of carrier cations mobility becomes an initial factor in enhancing the membranes conductivity. Moreover, the perfluoro sulfonate ionomers are not membranes of the cross-linked polymer. The EW value decrease leads to increasing the cations species number and expanding the membrane volume for the swelling.

The motion of water molecules in the polymer membranes is subjective with electrostatic counteraction by the cationic species; the water molecules mobility within membranes are diminished when the stronger interaction is present, and the membrane's diffusion rate will be slower with the reduction of water molecules. Furthermore, the cations species and water molecules' mobility in the polymer membranes is prominently crucial to comprehend the ionic movement in the membranes. In this scenario, the coefficient of water transmission *t*H2O and the permeability of water Lp are significant parameters; they also provide such particulars about transportation. One carrier cation dragged that much water molecules denoted tH2O holds a positive charge when cation transports within membranes. If this value becomes higher, the molecules of water intermingle with the cation species to the membranes more sturdily.

On the other hand, *L*p depicted that the rate of permeation of water molecules within membranes. The diffusion of water molecules arises more smoothly in the membranes when the value is higher. The *t*H2O value of the Na<sup>+</sup> and Li<sup>+</sup> form membranes depicted high values compared to the membranes of the H-form. The *L*p Na-form and Li<sup>+</sup> membranes are lesser than the membranes of the H-form. The Na<sup>+</sup> and Li<sup>+</sup> cations have sturdier counteractions compared to protons in the membranes with water molecules and avoid the diffusion of water molecules.

Moreover, the yield results delineated of the H-form membranes is the transportation of proton controlled by the hopping process, and the molecules of water are dragged hardly together at the time of proton transportation within membranes. In this case, the water molecules easily diffuse compared to Na-and Li-form membranes. The variation in *L*p and *t*H2O with respect to the EW value exhibits importance for water molecules with ion transport. The *t*H2O is not systematically varied in the proton membranes, with the increment of *L*p with EW value decrement. The two distinct parameters, water permeability and water transference coefficient, have better associations with the membranes conductivity. It is corroborated that the water molecules move more easily, in which membrane depicted higher ionic conductivity. The water molecules mobility within membranes correlated with the conductivity and is motivated by the cation species and the equivalent weight value. To envisage the interrelation between the cation species and the water mobility in elaborate, the analysis of the coefficients of self-diffusion DLi+ and DH2O was calculated by Li, and 1H PGSE-NMR are investigated. The values of *D*H2O are about 10<sup>10</sup> m<sup>2</sup> s <sup>1</sup> in the membranes. The acquired value for the proton Nafion 117 is very similar as investigated by Zawodzinski et al. in the temperature of 30°C. It is identified that the *<sup>D</sup>*H2O value of pure H2O at 30°C is 2.55 <sup>10</sup><sup>9</sup> <sup>m</sup><sup>2</sup> s 1 . So the molecules of water mobility in the membranes are decreased. The *D*H2O of the membranes enhances with reducing the EW value. The H-form membranes depict high values compared to the Na- and Li-form membranes. Those obtained outputs indicate that the water molecules transportation within membranes is decreased with the channel morphology of the cluster of ion zones and the interactivity by the species of a cation. Moreover, the molecules of water penetrate more rapidly in the Nafion membranes compared to the flemion membranes in the almost equivalent EW value. Also, it is fascinating that the polymer matrix membrane morphology impacts the membranes' conductivity. As a carrier ion, the movement of Li<sup>+</sup> is much connected to the water molecules transports in the membrane matrix. This is illustrated in **Figure 10**, here *D*Li<sup>+</sup> is illustrated versus *D*H2O of the similar

#### **Figure 10.**

*Mobility* u and *concentration* c *of carrier cations species in dissimilar membranes at the wholly hydrated state and the illustration of coefficient of self-diffusion of Li<sup>+</sup> cation* D*Li <sup>+</sup> within Li-form membranes versus water molecule* D*H2O [59].*

membranes. Generally, the diffusion phenomenon (small-range) is quicker than diffusion of longer-range is elucidated as inconsistent diffusion.

Moreover, the time-dependent *D*H2O illustrates that the molecules of water disperse in the heterogeneous region in the membranes. The areas of an ionic cluster are not the open area for the H2O diffusion, and the interaction of water molecules with SO3� and Li+ shows dissimilar exchange rates. All of the obtained coefficients of self-diffusion analyses for Li<sup>+</sup> cation and water molecule by the PGSE NMR procedure are correlated well with other investigations of ionic conductivity, water content, water permeability, and water transference coefficient. Moreover, it is becoming a potential tool to comprehend water and ion-molecule transportation performance within the membranes [58].

#### **6. Conclusion**

This chapter represented the energy storage application with results and the practical characteristics of IPMC polymer materials in the analogous field. This composite polymer and polymer matrix have been researched in detail in the potential application of flexible energy storage of electrical energy. The attributes create the IPMC polymer materials prominent and potential elements for substituting the conventional capacitors in different real-time applications. These whole chapter goals delineate the summary of IPMC polymer material on energy storage and its corresponding working principles. There is plenty of fabrication methods comprising the primary process of compositing membrane and electrode of membrane surface discussed in detail. The coefficient of electro-osmotic drag of methanol is varied with temperature directly proportional. Direct methanol fuel cells analysed at different temperatures and methanol concentration delineated the highest performances in 2 M solutions at 95°C. The Nafion-PVA membranes of 47 μm and 19 μm thickness depicted proficient response, though the protonic resistance is high of composite membranes. The Nafion film thickness is enhanced the electrical harvesting response considering the more water retention in its internal pores. The foaming ratio escalation modifies the structure internally of

#### *IPMC Based Flexible Platform: A Boon to the Alternative Energy Solution DOI: http://dx.doi.org/10.5772/intechopen.99434*

electrolyte membrane and enhances the harvesting phenomena, and that corroborated to increase storage of electric charge and modification of capacitance, with augmentation of water. The content of water in the membranes depicted the propensity of the increment of ionic cluster areas number with size though equivalent weight value decreased and the Li + form membranes fashioned the biggest regions of the ionic cluster. Also, the coefficients of water transfer and permeability denoted that in the Na- and Li-form membranes, the interaction of water molecules much sturdily with cations compared to proton when it can transport within membranes, and the molecule of water diffusion is decreased. The research analysis illustrated that surface area increment of IPMC by the etching and surface sanding enhances the gas generation rate of the IPMC electrolyser. The temperature increment of water effect on the IPMC electrolyser and the analysis data depicts the sharp enhancement of gas generation rate with the voltage applied to the generator ameliorates. Generally, the module's rotation is very less along with the gross amplitude of the 18 modules in the yaw, rolling and pitching motions is roughly 1 degree at 0.48 Hz. Moreover, the displacement in the z-direction is substantially high compared to the incident wave's amplitude and displacements of other directions. The experimental analysis delineated that gross power density at a particular time of a day sturdily fluctuated above 180 μW/m2 , along with power density of roughly 245 μW/m<sup>2</sup> with 292 μW/m<sup>2</sup> peak value. This polymer matrix system and its prominence application in electrical energy storage are yet to investigate more, and there are lots of parts that have to be explored in upcoming times. This chapter will also be beneficial in comprehending the IPMC polymeric matrix system to plenty of interested researchers in electro-active polymers. To be precise, the application of IPMC materials in electrical energy storage acts as guidance.
