Liquid Leakage Research Articles

Reversible, ultra-strong underwater adhesive based on supramolecular interaction for instant liquid leakage sealing and robust tissue adhesion

Underwater adhesives have great potential applications in biomedical fields. However, it is challenging to realize underwater adhesion due to screening by highly hydrated layer at the interface. To tackle this problem, here we present a novel strategy that combines hydrophobic association and supramolecular interactions to achieve robust adhesion at wet interfaces. Hydrophobic monomers (hexyl acrylate and styrene) are copolymerized with hydrophilic acrylic acid (AAc), and bifunctional host/guest assembly of β-cyclodextrin and adamantane to produce an adhesive. Herein, hydrophobic segments segregate to form hydrophobic microdomains both inside and at the interface. Internal hydrophobic clusters and host–guest interactions serve as physical crosslinks to improve the mechanical properties. Meanwhile, hydrophobic domains at surface play a critical role in expelling water and building a hydrophobic environment to minimize interference from water, where the hydrophilic units form hydrogen bonding, electrostatic attraction, coordination, and cation-π interactions to adhere on the surface. Lap shear tests indicate adhesion strength of about 92 ∼ 116 kPa on glass, copper, plastic, wood, and bone. Such a strong adhesion is independent of environment changes, including pH, PBS and NaCl solutions. More importantly, the adhesive shows excellent adhesion performance for bone, with adhesion strength up to 112.58 kPa in air and 91.51 kPa underwater. The strategy to combine hydrophobic interactions and supramolecular interactions may open a new avenue to the development of new adhesives for underwater adhesion and biological tissue.

Risk assessment of liquid ammonia tanks based on Bayesian network and Probit model

AbstractThis paper presents a quantitative risk assessment method to predict the potential risks of liquid ammonia tanks. The method combines probabilistic prediction and consequence assessment: the former is predicted by Bayesian networks derived from bow‐tie mapping, in which the conditional probabilities are determined by analytic hierarchy process, the latter is calculated based on numerical simulation of accident consequences and Probit probability model. The application results show that the method can be used for quantitative risk assessment of liquid ammonia storage tank, and the Bayesian network model is efficient and stable, which can realize risk prediction, accident causes analysis and risk mitigation analysis. Human errors during production or maintenance and corrosion are the main causes of liquid ammonia leakage. Toxicity has the greatest effect on the risk of liquid ammonia tanks. Risk mitigation measures can significantly reduce individual risk and societal risk. The obtained results provide meaningful guidance for the prevention and risk mitigation strategies of liquid ammonia leakage accidents, so as to improve the safety level of liquid ammonia during storage.

Atmospheric water harvesting by osmotic distillation and direct contact membrane distillation using hydrophobic hollow fiber membranes

The use of a liquid desiccant air dehumidifier is an energy-efficient technology that can improve both indoor air temperature and humidity. However, the risk of concentrated liquid desiccant leakage into the air conditioning system during dehumidification can corrode the system, negatively impact indoor air quality, and potentially harm residents. To address this issue, this study investigates the effectiveness of osmotic distillation (OD) and direct contact membrane distillation (DCMD) for dehumidification and regeneration, respectively. The study analyzes the impact of inlet operating parameters, including liquid desiccant concentration, temperature, and flow rate, and air flow rate on the dehumidification performance and stability of the OD process. Calcium chloride was utilized as the liquid desiccant in this study. The results indicated that the dehumidification performance of the OD process improved with a higher desiccant concentration and lower desiccant temperature. However, the desiccant flow rate did not have a significant impact on dehumidification performance. Furthermore, the dehumidification performance decreased with a higher inlet air flow rate, but the moisture removal rate increased. The OD process demonstrated stable operation during the dehumidification process. DCMD was effective for desiccant regeneration, and no scaling occurred due to the deposition of calcium chloride crystals. However, the permeation flux of DCMD decreased as the feed concentration increased due to a decline in the feed vapour pressure and an increase in concentration polarization effect. In conclusion, the experimental results indicated that OD can effectively dehumidify humid air, while DCMD is a viable option for desiccant regeneration.

Ultraflexible, cost-effective and scalable polymer-based phase change composites via chemical cross-linking for wearable thermal management

Phase change materials (PCMs) offer great potential for realizing zero-energy thermal management due to superior thermal storage and stable phase-change temperatures. However, liquid leakage and solid rigidity of PCMs are long-standing challenges for PCM-based wearable thermal regulation. Here, we report a facile and cost-effective chemical cross-linking strategy to develop ultraflexible polymer-based phase change composites with a dual 3D crosslinked network of olefin block copolymers (OBC) and styrene-ethylene-butylene-styrene (SEBS) in paraffin wax (PW). The C-C bond-enhanced OBC-SEBS networks synergistically improve the mechanical, thermal, and leakage-proof properties of PW@OBC-SEBS. Notably, the proposed peroxide-initiated chemical cross-linking method overcomes the limitations of conventional physical blending methods and thus can be applicable across diverse polymer matrices. We further demonstrate a portable and flexible PW@OBC-SEBS module that maintains a comfortable temperature range of 39–42 °C for personal thermotherapy. Our work provides a promising route to fabricate scalable polymer-based phase change composite for wearable thermal management.

Properties of Superhydrophobic and Acid–Alkali-Resistant Polyester Fabric Produced Using Plasma Processing

During the processes of production, storage, transportation and use of hazardous chemicals, acid–alkali corrosive liquid spatter and leakage would cause serious casualties. In order to protect the lives and health of staff, the surface of fabrics should be treated to obtain hydrophobicity and acid–alkali resistance. In this paper, polyester fabric was used as the base cloth, and polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) micro-powder were used as the functional materials to fabricate waterproof and breathable fabric with good acid–alkali resistance using a method of plasma pretreatment-impregnation- and plasma-induced crosslinking. The effects of PDMS, PTFE powder and plasma-induced crosslinking on the surface and physical and chemical properties of fabric were investigated. It was found that the use of PDMS and PTFE powder had little effect on the mechanical and wearing comfort properties. However, it could significantly improve the acid–alkali resistance, as the liquid repellent rate of the treated fabric surface was higher than 80%, and the penetration index was lower than 2%.

Tree-ring structured phase change materials with high through-plane thermal conductivity and flexibility for advanced thermal management

Phase change materials (PCMs) as one of the most promising latent heat storage materials have been applied for thermal management of electronic devices. Nonetheless, simultaneously endowing PCMs with high through-plane thermal conductivity and flexibility remains challenging. Herein, a coupling strategy combining scraping, hot compression, and roll-cutting is proposed to fabricate polydimethylsiloxane/paraffin/boron nitride (PDMS/PW/BN) composites. The BN alignment across the in-plane (x-y direction) was firstly obtained via scraping, then hot compression and roll-cutting were introduced to induce BN aligned across the through-plane (z-direction). Consequently, PW was wrapped by the cross-linked PDMS/BN network, thus forming a similar tree-ring structure to natural wood. The tree-ring structure effectively avoided the liquid leakage of PW, thus showing a high dimension retention ratio of 98 %. The vertical orientation of the BN network imparted the PCMs improved through-plane thermal conductivity of the PCMs to 2.16 W·m−1·K−1 at a BN loading of 13.0 wt%, showing a remarkable improvement of 943 % in comparison with PDMS/PW. Interestingly, the PCMs exhibited tunable thermal conductivity by triggering the melting-crystallization transition of PW. The in-situ X-ray diffraction indicated that the BN network rearrangement occurred during the phase transition. Furthermore, the good thermal management capability of PCMs was practically confirmed on working chips and via finite element simulation. This work presents a cost-effective approach for producing flexible PCMs with high through-plane thermal conductivity, which have the potential to be used in the thermal management of advanced electronics.

Investigation of self-adjusting cooling system for the autonomous underwater vehicle propulsion motor

Permanent magnet (PM) motors are widely employed in the autonomous underwater vehicle (AUV) propulsion because of their high efficiency and torque density. Since the AUV housings are sealed and narrow, motors are vulnerable to the risk of overheating, leading to dissolution of the winding insulation and demagnetization of the permanent magnets. In this study, a self-adjusting cooling scheme was proposed, which uses the hydrodynamic pressure to pump seawater into the cooling channel automatically. Firstly, the mathematical model of the flow field and heat transfer was established using equation derivations. Subsequently, to clarify the characteristics of the self-adjusting cooling system, the effect of the AUV speed on the thermal and fluid characteristics was investigated using computational fluid dynamics. Results show that the flow rate in the channel increases from 2 to 8.1 L/min as the AUV speed increases from 15 to 50 kn, resulting in the improvement of the heat transfer coefficient from 41 to 764 W/(m2∙K). Subsequently, the influences of inlet and outlet on the thermal characteristics were studied and found to be beneficial for improving the cooling performance. To investigate the spiral flow channels, the distribution coefficient kC and shape factor Rf were defined. Compared to the closed-cycle cooling system for the AUV propulsion motor, the proposed cooling system eliminated auxiliary devices such as pumps and heat exchangers, which makes it more compact and efficient for AUVs. However, introducing seawater into the AUV housing poses a risk of liquid leakage.

Research of the thermal storage properties of thermally conductive carbon fiber-reinforced paraffin/olefin block copolymer composite phase change materials with thermotropic flexibility

This study focuses on the fabrication and evaluation of paraffin (PA)/olefin block copolymer (OBC)/carbon fiber (CF) composite phase change materials (CPCMs) prepared using the melt impregnation process. The resultant PA/OBC/CF CPCMs exhibit superior thermal stability below 200 °C and maintain excellent shape stability at 60 °C. These characteristics are attributed to the alternating soft and hard segments of OBC, wherein the hard segments prevent liquid leakage from PA. The distinct structure of OBC further lends flexibility and recyclability to the PA/OBC/CF CPCMs. The latent heat of these CPCMs ranges from 169.1 to 197.6 J/g. Notably, the CPCMs variant (PA/OBC/CF-1) with 2 wt% CF addition retains 95 % of its initial latent heat even after 100 thermal cycles, thereby demonstrating superior cycling stability. The thermal conductivity of CPCMs with 10 wt% CF is 1.3 times that of pure PA. This significant improvement in thermal conductivity is attributed to the heat conduction pathways provided by the fibrous CF. These results indicate that the fabricated CPCMs offer substantial promise for utilization in low-temperature waste heat recovery applications.

New Developments in Detector and Bund Wall Standards to Mitigate the Risk of Hazardous Liquid Leaks

Ensuring early leak detection and implementing effective secondary containment systems are critical for preventing the dispersion of hazardous liquids and minimizing the casualties of a chemical accident. This study reviews the standards for leak detectors and their placement in various regions, as well as the key parameters involved in bund design such as bund capacity, bund wall height, and separation distance from the bund wall. In this study, Computational Fluid Dynamics (CFD) simulations are conducted considering storage tanks with heights (H) of 1.75 m, 3.5 m, and 7.0 m. The detection times using a level transmitter (LT) and a leak sensor are compared at eight monitoring points. Exclusively employing the leak sensor led to a significant detection time delay of up to 16 times, ranging from 0.5 s to 8.1 s depending on the placement of the leak sensors. However, the average rate of liquid level change was 3.0 mm/s, which demonstrates that the LT consistently detects leaks faster than the leak sensor at all monitoring points. Hence, the integration of an LT alongside a leak detector offers a valuable approach to expedite leak detection, regardless of the direction or location of the leak. Furthermore, the optimized separation distance between the storage tank and the bund wall is suggested. The analytical solution and numerical solution for a separation distance matches up to 95% for H=1.75 m. The separation distance increases as both the tank height and the height of the leak source increase. The relationship between the separation distance and the tank height exhibits a square root dependence on the liquid level from the leak point. The proposed detection method and optimized separation distance hold the potential to facilitate a revision of liquid storage and handling standards grounded in robust scientific and quantitative evidence.

An energy storage composite using cellulose grafted polyethylene glycol as solid–solid phase change material

AbstractPhase‐change material (PCM) has great thermal energy ability, which has been used as building material for energy conservation. While the most widely used solid–liquid PCM usually appeared leakage during the phase change transition. In order to overcome the leakage of solid–liquid PCM and prepare a viable building energy‐saving materials for indoor temperature regulation, thermal energy storage composites were prepared by utilizing cellulose grafted PEG as phase change material (PCM) and high‐density polyethylene (HDPE) as the substrate. The liquid leakage of PEG was solved after graft to fabricate solid–solid PCM. HDPE is beneficial for solving the leakage and improving the mechanical property by its secondary encapsulation. The synthesized Cellulose‐PEG was characterized by scanning electron microscopy (SEM), X‐ray diffractometer (XRD), and differential scanning calorimetry (DSC). Thermal and mechanical characteristics of the composite were explored. The outcomes revealed that: (1) PEG was successfully grafted to the surface of cellulose and Cellulose‐PEG showed solid–solid phase change behavior. (2) Both the melting‐cooling temperatures and the thermal stability of solid–solid wood plastic composite (SSWPC) had the potential as thermal energy storage material for temperature regulating. (3) The addition of Cellulose‐PEG adversely affected moisture resistance, flexural property, and impact strength due to the weak interface bonding. The physical and mechanical degradation was tolerable for applying situation where mechanical performance is less crucial.Highlights Cellulose‐PEG showed solid–solid phase change behavior without liquid leakage. High‐density polyethylene (HDPE) was used as the matrix to realize the second encapsulation of PCM. Cellulose‐PEG negatively influenced the physical and mechanical property of HDPE. Solid–solid wood plastic composite presented great thermal storage capacity for indoor temperature regulating.

Anti-leakage and recyclable phase change thermal conductive films with ultralow thermal impedance enabled by Field’s metal via the generation and internalization of metal oxides

The heat dissipation performance of a thermal interface material (TIM) is greatly dependent on its total thermal impedance, which can be effectively reduced by introducing a solid–liquid phase change material (PCM). However, previously reported phase change TIMs (PCTIMs) have been developed only based on organic PCMs with low thermal conductivities; thus, they cannot achieve low thermal impedance. Herein, Field’s metal (FM), which is a metal phase change material with a melting point of approximately 60 ℃, is first employed to develop a novel PCTIM with an ultralow thermal impedance. Trace oxidation is conducted on FM, and Bi2O3 and SnO are thus generated, followed by forming nanoscale particles by internalization. The formation of the nanoscale metal oxides increases the surface free energy and interfacial interaction force, thereby increasing the viscosity and improving the film-forming ability of the oxidized FM. The phase change thermal conductive films with different thicknesses, which are fabricated from the optimal oxidized FM, exhibit little liquid leakage, even at a pressure of 200 psi, and reach an ultralow thermal impedance of 0.03 cm2·K·W−1 at a thickness of 100 μm after the solid–liquid phase change, which is lower than those of the previously reported PCTIMs. The optimal film possesses good thermal reliability and recyclability, and shows a significantly better cooling effect than a commercial PCTIM with an identical thickness. These ideal characteristics make the FM-based phase change thermal conductive films up-and-coming in practical applications.

Analysis of Internal Flow Characteristics of the Bearingless Direct-Drive Centrifugal Pump System during Transient Start-Up

Traditional shaft-sealed centrifugal pumps exhibit problems, such as liquid leakage and reduced efficiency, due to mechanical seal failures. To address the issue, the bearingless direct-drive centrifugal pump system (BDDCPS) has been designed with bearingless motor technology. This may cause a new issue of rotor eccentricity displacement, which can lead to a reduction in pump performance. Compared to a stable state, the changes in characteristics, such as flow rate, head, and pressure, during the transient start-up process are more severe, increasing the likelihood of system failure and requiring greater attention. In order to ensure safety and reliable operation during the transient start-up process, this paper investigates the working principle of the BDDCPS and analyzes transient start-up characteristics with three different start-up methods. The external characteristics, pressure field distribution, velocity field distribution, and hydraulic losses analysis of the pump are determined for comparative analysis. Finally, it is found that the linear acceleration start-up method is the most suitable and efficient for the BDDCPS.

Experimental Study on a Novel Form-Stable Phase Change Material Based on Solid Waste Iron Tailings as Supporting Material for Thermal Energy Storage

To prevent liquid leakage during the phase transition of a phase change material (PCM), a novel form-stable PCM (FSPCM) based on LA/CIT/CNT was fabricated using a simple and facile direct impregnation method. The iron tailings (ITs) was calcinated at first. And then lauric acid (LA) was impregnated into the calcinated iron tailings (CITs) with carbon nanotubes (CNTs) as a thermal conductivity additive. Subsequently, the leakage tests and the properties of the prepared samples were investigated by diffusion-oozing testing (DOT), SEM, XRD, FTIR, DSC, TGA, and intelligent paperless recorder (IPR). DOT results showed that the impregnation ratio of LA into the CIT and CNT was up to 27.5% without leakage. SEM indicated that LA can be adsorbed into microscale pores and covered the surface of CITs and CNTs. FTIR spectra indicated that there was no chemical reaction during the preparation process. The melting and freezing temperatures of the prepared LA/CIT/CNT FSPCMs were measured as 45.24 °C and 39.61 °C, respectively. Correspondingly, the latent heat values were determined as 39.95 J/g and 35.63 J/g, respectively. The LA/CIT/CNT FSPCMs exhibited good thermal stability in the working temperature range, and its heat transfer efficiency was improved significantly by 69.23% for LA and 84.62% for LA/CIT FSPCM. In short, LA/CIT/CNT FSPCMs are a very promising material for thermal energy storage in practical low-temperature applications.

A Minireview of the Solid-State Electrolytes for Zinc Batteries.

Aqueous zinc-ion batteries (ZIBs) have gained significant recognition as highly promising rechargeable batteries for the future due to their exceptional safety, low operating costs, and environmental advantages. Nevertheless, the widespread utilization of ZIBs for energy storage has been hindered by inherent challenges associated with aqueous electrolytes, including water decomposition reactions, evaporation, and liquid leakage. Fortunately, recent advances in solid-state electrolyte research have demonstrated great potential in resolving these challenges. Moreover, the flexibility and new chemistry of solid-state electrolytes offer further opportunities for their applications in wearable electronic devices and multifunctional settings. Nonetheless, despite the growing popularity of solid-state electrolyte-based-ZIBs in recent years, the development of solid-state electrolytes is still in its early stages. Bridging the substantial gap that exists is crucial before solid-state ZIBs become a practical reality. This review presents the advancements in various types of solid-state electrolytes for ZIBs, including film separators, inorganic additives, and organic polymers. Furthermore, it discusses the performance and impact of solid-state electrolytes. Finally, it outlines future directions for the development of solid-state ZIBs.

Design of a stearic acid/boron nitride/expanded graphite multifiller synergistic composite phase change material for thermal energy storage

• Stearic acid was encapsulated by various fillers. • A shape-stabilized composite phase change material was prepared. • Thermal and cycling stability of the prepared composite are excellent. • Thermal conductivity of the prepared composite is 6.349 W•m −1 •K −1 . In order to solve the problems of low thermal conductivity and easy liquid leakage of a stearic acid (SA), the composite phase change material(PCM) was prepared by adding boron nitride (BN) and expanded graphite (EG) to melted SA, and its thermal conductivity, crystal structure, chemical stability, thermal stability, cycle stability, leakage characteristics, heat storage/release characteristics, and temperature response characteristics were characterized. The results showed that the addition of BN and EG significantly improved the thermal conductivity of the material, and they efficiently adsorbed melted SA. The maximum load of SA was 76 wt. % and there was almost no liquid leakage. Moreover, the melting enthalpy and temperature were 154.20 J • g − 1 and 67.85°C, respectively. Compared with pure SA, the SA/BN/EG composite showed a lower melting temperature and a higher freezing temperature. In addition, when the mass fraction of BN and EG was 12 wt. %, the thermal conductivity of the composite was 6.349 W • m −1 • K −1 , which was 18.619 times that of SA. More importantly, the composite showed good stability for 50 cycles of heating and cooling, and the SA / BN / EG-12 hardly decomposes below 200°C, which implies that the working performance of the composite PCM is relatively stable within the temperature range of 100°C. Therefore, the composite can exhibit excellent thermal stability in the field of building heating.

Droplet impact on a microhole through a partially wetting surface

In this study, we thoroughly investigate the impact dynamics of water droplets on a partially wetting substrate with a single hole. By conducting experiments using de-ionized water droplets and high-speed imaging, we observe various outcomes, including downward jetting without pinch-off, jetting with single and multiple pinch-offs, and the intriguing emergence of an upward jet during droplet recoil. A regime map is constructed to establish the relationship between the dynamics of the jet and the Weber number. We find the small amount of liquid leakage through the hole has a negligible effect on the maximum spreading of the droplet. We analyze the behavior of the downward jet resulting from droplet impact in terms of its length, speed, and breakup characteristics. The scaling relation between the maximum jet length before its breakup and the Weber number is derived and compared with experimental data. We find that the growth of the downward jet length follows a consistent power-law relationship with time regardless of impact velocity, while the maximum jet velocity scales linearly with the impact velocity, confirming the hydrodynamic focusing theory. The size of the head satellite droplet formed during the jet pinch-off process remains nearly constant across different Weber numbers. Additionally, we investigate the volume of ejected liquid through the microhole, observing an initial increase with the Weber number followed by a saturation point. The occurrence of the upward jet during droplet recoil is a significant finding, and we analyze its diameter, height, and velocity in relation to the Weber number.

Sustainable Porous Scaffolds with Retained Lignin as An Effective Light-absorbing Material for Efficient Photothermal Energy Conversion.

Organic phase change materials (PCMs) are promising to utilize thermal energy from solar radiation for photothermal energy conversion. However, the issues of poor photo absorption and liquid leakage greatly restrict their practical application. Herein, a sustainable porous scaffold comprising periodate oxidized wood (POW) as the supporting material and in situ retains lignin as the light-absorber dopant are demonstrated. The π-π stacking ability of lignin molecules endows the retained lignin with efficient photonic energy harvesting characteristics for fast thermal conductivity to reach a higher maximal energy storage volume. The inherently porous structure of the POW scaffold enables excellent shape-stability, which bypasses the liquid leakage problem. The resulting POW/PCM composites exhibit superior comprehensive performance, including enhanced light absorption capacity, high photothermal conversion efficiency (≈86.7%), and high latent heat of 151 J g-1 . Furthermore, the POW/PCM composites also possess the ability to maintain a relatively constant indoor temperature when fixed atop the model house roof, showing great potential for their practical applications in the thermal regulation of intelligent buildings. This work not only paves a new way to obtain sustainable and effective porous scaffolds for sufficient photothermal energy conversion but also provides more possibilities for their practical application in the future.

Comprehensive use of fossil derivative: High value-added conversion of waste plastics to thermal energy storage materials

As one of the most common fossil derivatives, plastic is indispensable in daily life because of its promising mechanical properties, chemical stability, and easy accessibility. However, plastics still present a huge burden on the global environment due to their high production volume, difficulty with degradation and low recycling rate. At the same time, global primary energy reserves are decreasing, thus achieving highly efficient use of energy has become a hot topic of research. Herein, the waste plastics can be utilized as a supporting material and encapsulation the phase change materials through intermolecular hyper-crosslinking reaction with the assistance of Lewis acids. To illustrate the effect of porous structure on the thermophysical properties and energy storage characteristics of the obtained materials, three aromatic crosslinkers, triphenylphosphine, triphenylbenzene, and benzene were examined regarding their performance on the Fridel-Crafts reactions. It is found that the obtained materials bearing a thermal conductivity and latent heat of 0.22 W/mK and 145.7 J/g, respectively, without liquid leakage.

Form-stable microencapsulated phase change materials for efficient solar thermal energy storage

Phase change materials (PCMs), renowned for their exceptional heat storage capabilities, have been extensively utilized in solar energy utilization. However, the persistent challenge of liquid leakage during their use remains unresolved. In this study, a promising microfluidic encapsulation technology is presented, leading to the development of a novel phase change heat storage microcapsule. Differential scanning calorimetry measurements confirm the retention of over 88% of the latent heat of the phase change material (up to 171.8 J/g). Additionally, CFD modeling demonstrates that the geometric structure of the microcapsules significantly enhances heat transfer, effectively addressing the issue of low heat transfer efficiency in PCM systems. Leakage tests have demonstrated the exceptional cyclic stability of microcapsule encapsulation, as it exhibits no leakage even after undergoing 100 consecutive melting-freezing cycles. Moreover, it experiences only a minimal 4.2% loss in latent heat. The incorporation of microcapsule encapsulation into phase change heat storage technology opens up exciting opportunities for harnessing the full potential of phase change materials.

Electrochemical Characteristics of Elastic, Non-Polar Polyurethane-Based Polymer Gel Electrolyte for Separator-Less Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have undergone countless enhancements in the past decade, mainly improvements in the basic components: electrodes, electrolyte, and separator. The separator, which acts as a physical barrier between the two electrodes, does not directly participate in the charge and energy storage.However, it is involved in the safety, form factor, and packaging density of the LIBs. While it occupies relatively less internal space than other components, the separator can be replaced with active materials such as gel polymer electrolytes (GPEs) which can serve as both the electrolyte and physical barrier between the electrodes. GPEs can potentially minimize the risks of liquid electrolytes, including flammability, electrolyte leakage, and explosion. Here we report the characteristics of polyurethane (PU)-based gel swollen in concentrated electrolyte solutions in separator-less cells. The poreless PU-based gel electrolyte conducts lithium ions, while preventing internal short-circuits. This is attributed to the presence of soft segments, which allow ion transport, and hard segments, which ensure mechanical integrity. Electrochemical measurements carried out in LFP half cells and symmetric Li cells revealed that the separator-less cells were operable between 0.2 C to 1 C rates, and that during long term cycling, the cells achieved stable Li electroplating overpotential, as the number of cycles increased.