Low-cost Energy Storage Materials Research Articles

Heteroatom-doped and graphitization-enhanced lignin-derived hierarchically porous carbon via facile assembly of lignin-Fe coordination for high-voltage symmetric supercapacitors

Lignin-derived carbon materials are widely used as electrode materials for supercapacitors. However, the electrochemical performance of these materials is limited by the surface chemistry and pore structure characteristics. Herein, a novel and sustainable strategy was proposed to prepare heteroatom-doped lignin-derived carbon material (Fe-NLC) with well-developed pore size distributions and enhanced graphitization structure via a facile lignin-Fe coordination method followed by carbonization. During carbonization, Fe3+ in lignin-metal complexes evolve into nanoparticles, which act as templates to introduce porous structures in carbon materials. Also, the lignin-Fe coordination structure endows the material with a higher graphitization during carbonization, thereby improving the structural properties of the carbon materials. Due to the removal of Fe3O4 template, the obtained Fe-NLC possessed reasonable pore distribution and nitrigen/oxygen (N/O) functional groups, which can improve the wettability of materials and introduce pseudocapacitance. Accordingly, Fe-NLC possesses a notable specific capacitance of 264 F/g at 0.5 A/g. Furthermore, a symmetric supercapacitor Fe-NLC//Fe-NLC with a high voltage window (1.8 V) was constructed. The symmetric supercapacitor exhibits a maximum energy density of 15.97 Wh/kg at 450 W/kg, demonstrating well application prospects. This paper proposes a novel approach for preparing carbon materials via lignin-metal coordination to provide an alternative way to explore sustainable and low-cost energy storage materials.

Performance optimization of a conical solar distillation system with and without stainless-steel balls as low-cost sensible storage: Experimental study and comparative analysis

An experimental study of a conical solar distiller's usage of inexpensive energy storage material to increase distillation yield. Stainless-steel balls are utilized in experiments because they increase the surface area of the water and are excellent energy storage devices. The goal of this research is to determine the optimal distance between the stainless-steel balls (with a fixed diameter of 1.4 cm) as a low-cost energy storage material to improve the productivity of conical solar stills. As a result, three identical conical distillates were produced. Experiments are carried out over the course of two days. On the first day, the first distiller is free of stainless-steel balls, the second distiller has a distance of 3 cm between the stainless-steel balls, and in the third distiller there are stainless-steel balls at a distance of 4 cm. The second day, the first distilled is still witness. The second and third distillers have stainless-steel balls placed at the bottom of the basin at distances of 5 and 6 cm, respectively. The depth of the brine in the basins is 1.4 cm. The distillation productivity with storage of stainless-steel balls (a diameter of 1.4 cm) with a distance of 3 cm between the stainless-steel balls achieves a maximum yield of 9500 g/m2 compared to the distillation yields with storage of stainless-steel balls with a distance of 4, 5, and 6 cm between the stainless-steel balls, which amounted to 8800, 8200, 7400, and 5750 g/m2, respectively. The optimal distance between the stainless-steel balls was found to be 3 cm, with an improvement rate of 65.22 %. Finally, conical solar energy with stainless-steel balls as a low-cost energy storage material with diameters of 1.4 cm, and a distance of 3 cm between the stainless-steel balls is still optimal.

Experimental study of the impact of low-cost energy storage materials on the performance of solar distillers at different water depths

In the current research, a low-cost energy storage material was utilized to improve the performance of single-slope solar distillers. To this end, a conventional distiller was modified with low-cost energy storage materials by adding twenty-five spherical salt balls and seventeen sponges to the bottom of the basin at different water depths, and its performance was examined under the climate of Al- Hilla, Iraq. Therefore, two cases were tested; 25 salt balls + 17 sponges in 1.5 cm depth of water (Case 1) and 25 salt balls + 17 sponges in 2 cm depth of water (Case 2), and their results were compared with the conventional solar distiller. It was found that using reasonable energy storage materials (salt balls and sponges) has a good role in increasing the productivity of modified solar distillers. Also, the daily accumulated productivity of modified solar still (MSS) for Case 1 was higher than that for Case 2 and CSS by about 16.86% and 44.32%, respectively. The maximum productivity was attained for Case 1, which was 1934 g/m2, 1655 g/m2, and 1340 g/m2 for both modified solar still (MSS-SBS) for Case 2 and CSS, respectively. Finally, it is recommended to use low-cost energy storage materials such as salt balls and sponges with a minimum depth of basin water to improve the productivity of the solar still.

An experimental comparative analysis of the appropriateness of different sensible heat storage materials for solar cooking

Solar energy is a significant energy source of outstanding sustainability, mainly used for heating and power production. There are numerous energy storage materials through which the performance enhancement of different solar heating systems is possible. In the present work, three different sensible heat storage materials, such as blackened pebbles, small pieces of masonry bricks, and small aluminium balls, have been experimentally studied for their thermal storage capacity inside a hot box cooker. All these materials have been used over the cooking plate of the tested cookers. Only three configurations have been developed to perform the stagnation and sensible heat tests. Notably, the authors have focused on a low-cost solution to enhance the thermal efficiency of a box cooker using sensible heat storage materials, especially for people from remote or rural areas. Even, a less educated consumer can easily apply the suggested technique to a box cooker through the Do-It-Yourself method. Results of the cooking trials have been found in favour of consumers and show the appropriateness of low-cost energy storage materials. These results also indicate a possibility of adopting all the tested models, mainly the cooker with aluminium balls, which is the best-configured cooker. This cooker has a thermal efficiency of about 59.61 %, cooking power of about 75.21 W, and thermal storage capacity of around 09 h/day. The estimated cost is approximately $47.06 for the best-configured cooker and its payback period is about 3.11 years.

Augmenting the productivity of tubular solar still using low-cost energy storage materials

Productivity improvement is one of the high-priority areas in the development of solar stills. The present work describes the use of some low-cost energy storage materials such as sand, gravels, and black granite as potential candidates to improve the productivity of the tubular solar still (TSS). The experimental studies have been carried out at Nagpur (21.1241° N, 79.0023° E) to investigate the effects of these materials on the productivity of the TSS. Three separate TSS experimental setups have been made for each energy storage materials. These include (a) 5kg of fine sand (0.125-0.25-mm grain size), (b) small gravels (20-30mm), and (c) black granite (5-mm thickness) placed in the absorber basin of individual TSS setup, separately. The experiments have been performed by varying basin water depth at 0.5cm, 1cm, and 2cm, for each case. The results show that for water depth of 0.5cm, productivity of TSS-Black granite is enhanced by 10.5% and 34.88% as compared to TSS-Gravel case and TSS-Sand case, respectively. Thermal efficiency and exergy efficiency of TSS-Black granite at 0.5-cm water depth is enhanced by (32.4%, 9.8%) and (92.1%, 21.9%) as compared to TSS-Sand case and TSS-Gravel case, respectively. Furthermore, it has been estimated that the cost of production of freshwater using TSS-Black granite is lowest among all selected combinations.

Achieving in-situ hybridization of NaTi2(PO4)3 and N-doped carbon through a one-pot solid state reaction for high performance sodium-ion batteries

The development of green, sustainable and low-cost energy storage materials through simple and environmental friendly routes is of great significance for futural large-scale energy storage systems. Due to its unique sodium super ionic conductor (NASICON) structure, polyanion-type NaTi2(PO4)3 (NTP) is regarded as one of the promising potential cathode materials for sodium-ion batteries (SIBs). However, its practical application has been impeded by its intrinsic poor conductivity for unmodified NTP. To resolve this issue, this work hybridizes the NTP with a N-doped carbon matrix (NC) through a facile one-pot solid state reaction, taking an organophosphonic acid (ethylenediamine tetramethylene phosphonic acid, EDTMPA) as source material providing carbon, nitrogen and phosphorous element at the same time. The as-prepared NTP@NC composite not only possesses improved electrical conductivity, but also mitigates particle agglomeration during prolonged charge-discharge cycles. As a result, the NTP@NC composite exhibits an outstanding sodium storage behavior, in terms of a high specific charge capacity (105.6 ​mA ​h ​g−1 at 0.2 ​C with 87.3% initial coulombic efficiency), an excellent cycle performance (101.2 ​mA ​h ​g−1 charge capacity after 100 cycles at 0.2 ​C with a charge capacity retention of 95.8%) and outstanding rate capabilities (103.6 ​mA ​h ​g−1 charge capacity at 1 ​C and 71.5 ​mA ​h ​g−1 at 5 ​C, respectively).

Waste-biomass tar functionalized carbon spheres with N/P Co-doping and hierarchical pores as sustainable low-cost energy storage materials

Biomass tar has exhibited promising potential for fabricating carbon-based functional materials. In this study, carbon materials with hierarchical pores, N/P co-doping, and oxygen-rich functional groups were prepared from glucose and biomass tar via a hydrothermal treatment combined with H3PO4 activation strategy and their electrochemical performances were evaluated. The results showed that the coating of tar inhibited agglomeration of carbon sphere derived from glucose and regulated its surface properties, resulting in hierarchical porous structure and surface functional groups. During thermal treatment, the resultant carbon materials were appropriately self-heteroatom doped by N and P from tar and H3PO4, respectively. Due to the unique structure, the specific capacitance of as-prepared carbon electrode was 199 F g−1. The symmetric TGC-600 capacitor showed excellent electrochemical properties with specific capacitance of 175 F g−1 and energy density of 6.1 Wh kg−1. Furthermore, TGC-600 capacitor showed superior cyclic stability, the capacitance retention was around 92% after 5000 runs. This study offered a green and low-cost utilization approach for biomass tar to prepare supercapacitor with excellent electrochemical performance.

Preparation, characterization and some electrochemical study of waste derived iron Oxide-Carbon nanocomposite

Utilization of nanoparticles have seen significant growth as a filler material in different technological and product development. Iron oxide particles are found important due to their special characteristics such as; natural high abundance, low cost, robustness, low toxicity, high surface to volume ratio etc. The preparation of iron oxide nanoparticles using Wealth out of Waste (WoW) process is gaining much interest due to the economic point of view and environmental concern. In the current work, iron oxide nanoparticles with size 46 nm have been prepared by chemical method, using waste iron scrap obtained from mechanical lathe machines. Waste plastic and iron oxide nanoparticles, has been utilized in the pyrolysis process at 700 °C in a fixed bed pyrolysis reactor to prepare iron oxide–carbon composite. The electrochemical study of the composite was carried out and achieved specific capacitance to be 150 F/g and energy density to be 187.50 Wh/kg, which is comparable or even better than some other composite such as Fe3O4/CNT composite, Fe2O3 nanotube arrays, FeOOH rods and Fe3O4/CNF composite. The prepared Fe3O4-carbon composite is significant for reducing plastic waste, iron waste and providing low cost energy storage material.

Thermal performance evaluation of a solar air heater integrated with helical tubes carrying phase change material

Abstract In this present work, the efforts have been made to improve the efficiency of solar air heater (SAH). For this, total two models have been developed. There is one reference model SAH-A and one modified model SAH-B which is integrated with paraffin wax as a low cost energy storage material. Furthermore, model SAH-B is further modified into a new model SAH C which is integrated with a specific mixture of paraffin wax and Granular coarbon powder (GCP). For better heat storage capacity of the aforesaid energy materials, helical tube of copper made has been considered as a container. Both the models of air heater (SAH-B and SAH C) have been experimentally tested on natural and forced convection under the climatic conditions of Moradabad city, India. Results show that SAH- C is better over SAH-A and SAH-B in performance comparison. Thermal efficiency of SAH C is found to be 79.10%, whereas it is found around 57.41% for SAH-B and around 50% for SAH-A. The other major parameter is heat transfer coefficient and for SAH C it is found to be 411.05 W/m2K, whereas it is found around 389 W/m2K for SAH-B and around 249.19 W/m2K for SAH-A. The maximum exhaust temperature of SAH C is reported to be 52.5 °C, whereas it is observed around 46.9 °C for SAH-B and about to be 44.7 °C for SAH-A. The main parameters of the present work summarizes that the model SAH C is an economic and optimum model for space heating, timber seasoning, drying operations etc. The total cost of the best configured SAH C model is only $67.

Amorphous Carbon Nanotubes-Nickel Oxide Nanoflower Hybrids: A Low Cost Energy Storage Material.

Amorphous carbon nanotubes (a-CNTs) have been synthesized by a simple low-temperature process and have been grafted with chemically synthesized nickel oxide microflowers with different concentrations. The phase and morphology of the as-prepared pure and hybrid samples were characterized by X-ray diffraction and field emission scanning and transmission electron microscopes. Thermal properties of the samples were estimated by using thermal gravimetric and differential thermal analysis. The optical properties of the sample were characterized by UV–vis spectroscopic, Raman spectroscopic, and Fourier-transformed infrared spectroscopic analysis. The electrochemical performance of all hybrid samples has been done in detail for different scan rates as well as from charge–discharge analysis. It has been seen that because of the nickel oxide grafting, the electrochemical performance of pure a-CNTs gets enhanced significantly. The value of the specific capacitance of the hybrid comes out to be around 120 F/g for the best sample, which is almost 12 times higher compared to that of the pure a-CNTs. The result has been explained in terms of change in effective surface area as well as change in conductivity of the hybrid samples.

Layered and Tunneled Manganese Oxides As Battery Cathode Materials - the Role of Electrochemically Active and Inert Metal Cations

Fundamental studies involving the impact of physical and chemical properties of materials on their electrochemical properties are critical to the rational development of battery materials which may address the present and future requirements for stationary and portable power. For large scale batteries, the use of environmentally benign and low cost energy storage materials is desired. Manganese-based materials are desirable in this regard as they are environmentally friendly, inexpensive, and can be prepared using scalable, aqueous based synthesis methods. Preparation, characterization, and battery electrochemistry of two promising structural motifs of manganese oxides will be described, specifically tunneled (hollandite) and layered (birnessite) crystallographic structures. The use of complimentary bulk (synchrotron based diffraction, thermogravimetric analysis, optical emission spectroscopy) and local (transmission electron microscopy based atomic imaging, nanodiffraction and electron energy loss spectroscopy) to elucidate structures of as-prepared, electrochemically reduced and oxidized materials will be highlighted. The impact of crystallite size will also be discussed. Hollandites (Mx’Mn8O16) are one-dimensionally (1D) structured materials consisting of octahedral units of edge-sharing manganese oxide octahedra which interlink to form tunnels of 2 x 2 dimensions. Bimetallic hollandite type materials have been prepared where cations with 1+ or 2+ charge partially occupy locations within the manganese oxide tunnels, and the Mn cations possess mixed 3+ and 4+ oxidation states. Typically, the ion located within the tunnel (M’) is electrochemically inert (i.e. K+); however, silver hollandite is an interesting case as the Ag+ cationic center is potentially electrochemically active. The electrochemistry of potassium and silver based hollandites in lithium-ion and beyond lithium-ion battery systems will be described. The impact of the structural M’ cation and the role of oxygen vacancies on ion transport will be discussed. A novel recyclable battery electrode will also be described, which provides full restoration of initial capacity after a facile regeneration process. Birnessite (Mx’MnO2), a layered manganese oxide, exists as a monoclinic crystal comprised of layers of edge-sharing manganese-oxygen octahedra (MnO6) with cations positioned between the layers. Although birnessite can be formed without any interlayer cations, monovalent (i.e. Na+, K+, Li+, Cs+) or divalent (Mg2+ or Cu2+) cations can also be incorporated between the layers. The impact of an electrochemically active interlayer cation, copper (Cu2+), on capacity and structural integrity of the birnessite structure upon discharge-charge cycling will be described, including a detailed view of the Mn and Cu oxidation state changes along with variations of the local neighboring atom environments around the Mn and Cu centers.

Reactions of graphene supported Co3O4 nanocubes with lithium and magnesium studied by in situ transmission electron microscopy

Reaction beyond intercalation and the utilization of metal ions beyond lithium-ions are two promising approaches for developing the next generation of high capacity and low cost energy storage materials. Here, we use graphene supported Co3O4 nanocubes and study their reaction with lithium, magnesium and aluminum using in situ transmission electron microscopy. On lithiation, the Co3O4 nanocubes decompose to Co metal nanoparticles (2 to 3 nm) and embed in as-formed Li2O matrix; conversely, the CoO nanoparticles form on the Co site accompanying the decomposition of Li2O in the delithiation process. The lithiation process is dominated by surface diffusion of Li+, and graphene sheets enhance the Li+ diffusion. However, upon charge with magnesium, the Mg2+ diffusion is sluggish, and there is no sign of conversion reaction between Mg and Co3O4 at room temperature. Instead, a thin film consisting of metal Mg nanoparticles is formed on the surface of graphene due to a process similar to metal plating. The Al3+ diffusion is even more sluggish and no reaction between Al and Co3O4 is observed. These findings provide insights to tackle the reaction mechanism of multivalent ions with electrode materials.

Improving the yield of fresh water in conventional solar still using low cost energy storage material

As there is a larger need for drinking water, expensive methodologies are employed in order to get portable drinking water. This work aims at improving the yield of freshwater from a conventional solar still using the different low-cost energy storage material. Theoretical and experimental studies are carried out to analyze the performance of a single slope solar still. From this study, it is observed that the yield of freshwater from the solar still with spherical ball salt storage achieves the maximum yield of 3.7kg/m2 as compared to a conventional single slope solar still with sponge and without any storage material as 2.7 and 2.2kg/m2 respectively. The deviations between theoretical and experimental values for with spherical ball salt storage, with sponge and conventional solar still are found as 16.1%, 9.7% and 4.0% respectively. Payback period of the present solar still is found as 4.3months as it is quicker than other conventional single slope solar still. Finally, single slope solar still with spherical ball heat storage gives low cost of water.

Cycle stability and dielectric properties of a new biodegradable energy storage material

A biodegradable low-cost energy storage material has been obtained by using a self-assembly nanocomposite gelatin and graphene flakes. The blends with various ratio of graphene and gelatin have been prepared and characterized by Raman spectroscopy, cyclevoltammetry measurements, chronopotentiometry measurements and impedance spectroscopy. The ability of the biopolymer to bind the water–glycerol molecules and the graphene flakes leads to an improvement of the dielectric properties with a value of the surface capacitance of about 3 orders higher (10mFcm−2) than that measured for the device based on activated carbon. An electrical oxidation at the anode contact has been observed by applying to the device a higher bias voltage. The modified active material exhibits an enhancement of the cycle stability with a further increase of the surface capacitance (100mFcm−2) and of the respective specific capacitance up to a value of about 380Fg−1.

Highly specific capacitance materials constructed via in situ synthesis of polyaniline in a cellulose matrix for supercapacitors

On the basis of the requirements for both biobased economy and energy storage materials, we are interested in using cellulose-based microporous film as a template for in situ synthesis of polyaniline (PANI). Multifunctional carbon nanotube (CNT)/cellulose composite films were also prepared from a CNT/cellulose suspension in a NaOH/urea aqueous system. Subsequently, PANI was synthesized in situ in the pores of cellulose and CNT/cellulose substrates to construct PANI/cellulose (PC) films and PANI/CNT/cellulose (PCC) films, respectively. Both PC and PCC films were flexible and exhibited a highly specific capacitance and good cycle stability. With the addition of CNTs, the specific capacitance of the PCC films as supercapacitor materials was significantly improved. Moreover, a homogeneous structure intertwined with the cellulose, CNTs and PANI appeared in the composite films, indicating good miscibility. This work has provided a new approach to the fabrication of flexible, lightweight, highly effective, and low-cost energy storage materials, broadening the applications of cellulose.