In situ self‐template synthesis of cobalt/nitrogen‐doped nanocarbons with controllable shapes for oxygen reduction reaction and supercapacitors

Shape‐controlled Co/N‐doped nanocarbons derived from polyacrylonitrile (PAN) were synthesized by a one‐step in situ self‐template method followed by a pyrolysis procedure. This is the first study to tune the nanostructure of Co/N‐doped carbon materials by providing a metal salt as the template and additive. The moderate surface area (699.47 m² g^?1), highly developed pore structure, homogenous Co and N doping and designed “egg‐box” structure impart Co/N‐doped cross‐linked porous carbon (Co/N‐CLPC) with excellent electrocatalytic activity and capacitive performance. This material displayed an onset potential of 0.805 V (vs RHE), a current density of ?5.102 mA cm^?2, excellent long‐term durability, and good resistance to methanol crossover, which are comparable with the characteristics of a commercial 20‐wt% Pt/C catalyst. In addition, Co/N‐CLPC demonstrated a high specific capacitance of 313 F g^?1 at 0.5 A g^?1, notable rate performance of 63% at 50 A g^?1, and good cycling stability of 104.8% retention after 5000 cycles when used as a supercapacitor electrode. This method enables new routes to obtaining Co/N‐doped nanocarbons with shape‐controlled structures for energy conversion and storage applications.     

Morphology‐dependent electrochemical performance of nitrogen‐doped carbon dots@polyaniline hybrids for supercapacitors

In this work, the binary N‐CDs@PANI hybrids were fabricated by introducing zero‐dimensional nitrogen‐doped carbon dots (N‐CDs) into reticulated PANI. Firstly, N‐CDs were prepared by one‐pot microwave method, and then, the N‐CDs were introduced into in situ oxidative polymerization of aniline (ANI) monomer. The N‐CDs with abundant functional groups and high electronic cloud density played a significant role in guiding the polyaniline‐ordered growth into intriguing morphologies. Moreover, morphology‐dependent electrochemical performances of N‐CDs@PANI hybrids were investigated and N‐CDs improve static interaction and enhance the special capacitances in the N‐CDs@PANI hybrids. Especially, the specific capacitance of PC4 hybrid can reach 785 F g^?1, which exceed that of pure PANI (274 F g^?1) at current density of 0.5 A g^?1 according to three‐electrode measurement. And the capacitance retention of the PC4 hybrid still keeps 70% after 2000 cycles of charge and discharge. The N‐CDs@PANI hybrids can have potential applications in electrode materials, supercapacitors, nonlinear optics, and microwave absorption.     

One‐pot synthesis of composite NiO/graphitic carbon flakes with contact glow discharge electrolysis for electrochemical supercapacitors

Thanks to their high power density and degree of reversibility, supercapacitors are electrochemical devices that narrow the gap between secondary batteries and traditional dielectric capacitors in the traditional Ragone plot. However, their use is still hindered by their capability to achieve higher energy density. In this work, we present a one‐pot synthesis procedure of composite graphitic carbon flake‐supported NiO for electrochemical energy storage application. We used cathodic contact glow discharge electrolysis by applying 120 Vdc terminal voltage between a thin Pt wire, slightly submerged in an aqueous solution of NiSO₄(H₂O)₆ + Na₂SO₄, and a large surface area carbon graphite anode. Strong active species generated within the micro‐plasma volume locally reduce the nickel precursors to form NiO materials, while at the anodically polarized graphite rod, the forces holding the graphene layers together are weakened by ion/solvent intercalation producing micrometer‐sized graphitic carbon flakes. The morphological characterization is carried out by electron microscopy, energy dispersive X‐ray spectroscopy, powder X‐ray diffraction, and micro‐Raman spectroscopy. Cyclic voltammetry, constant‐current charge/discharge, and electrochemical impedance spectroscopy in 5 mol l^?1 KOH solution are carried out to evaluate the electrochemical energy storage performance of the material. We show that carbon flake‐supported NiO exhibits the dual combination of electric double‐layer capacitance with faradic behavior, giving 495 F g^?1 specific capacitance at 2 A g^?1 current density. Copyright © 2015 John Wiley & Sons, Ltd.     

Lignin‐derived heteroatom‐doped porous carbons for supercapacitor and CO2 capture applications

The present study reports the economic and sustainable syntheses of functional porous carbons for supercapacitor and CO₂ capture applications. Lignin, a byproduct of pulp and paper industry, was successfully converted into a series of heteroatom‐doped porous carbons (LHPCs) through a hydrothermal carbonization followed by a chemical activating treatment. The prepared carbons include in the range of 2.5 to 5.6 wt% nitrogen and 54 wt% oxygen in its structure. All the prepared carbons exhibit micro‐ and mesoporous structures with a high surface area in the range of 1788 to 2957 m² g^?1. As‐prepared LHPCs as an active electrode material and CO₂ adsorbents were investigated for supercapacitor and CO₂ capture applications. Lignin‐derived heteroatom‐doped porous carbon 850 shows an outstanding gravimetric specific capacitance of 372 F g^?1 and excellent cyclic stability over 30,000 cycles in 1 M KOH. Lignin‐derived heteroatom‐doped porous carbon 700 displays a remarkable CO₂ capture capacity of up to 4.8 mmol g^?1 (1 bar and 298 K). This study illustrates the effective transformation of a sustainable waste product into a highly functional carbon material for energy storage and CO₂ separation applications.     

Cobalt oxide nanosheets anchored onto nitrogen‐doped carbon nanotubes as dual purpose electrodes for lithium‐ion batteries and oxygen evolution reaction

Transition metal oxides (TMOs) have been extensively explored as promising electrode materials for electrochemical energy storage and catalysis. However, TMOs intrinsically have low electronic conductivity and suffer severe volume change during electrochemical cycling. In this study, we develop an effective strategy to enhance conductivity and buffer volume changes of TMOs, in which networked nitrogen‐doped carbon nanotubes (N‐CNTs) are incorporated into Co₃O₄ nanosheets system. Based on the whole mass of Co₃O₄ and N‐CNT, the composites can maintain a stable discharge capacity of ~590 mAh g^?1 after 80 cycles at a current density of 0.5 A g^?1. Moreover, the composites also exhibit greatly enhanced catalysis ability towards oxygen evolution reaction (OER), ie, small Tafel slope of 84 mV dec^?1, low overpotential of 310 mV at a current density of 10 mA cm^?2, and almost no activity decay throughout 30‐hour continuous operation. This study lays a new route for smartly designing advanced electrode materials for energy storage and electrochemical catalysis.     

The electrochemical properties of reduced graphene oxide film with capsular pores prepared by using oxalic acid as template

By using oxalic acid (OA) as template and reducer, a novel approach is developed to prepare reduced graphene oxide films with capsular pores (C‐rGOFs) under a hydrothermal condition. The effect of preparation conditions including concentrations of OA and reaction temperatures on the films' structure and capacitive performances has been systematically investigated. The optimal C‐rGOF shows uniform capsule‐like morphology and exhibits a density of 1.18 g cm^?3. Tested by using a two‐electrode system, the optimal film shows gravimetric specific capacitance of about 234.9 F g^?1 and volumetric specific capacitance of 277.2 F cm^?3. Additionally, the optimal film which shows good rate capability can retain 63.9% of initial capacitance at high scan rate of 1.0 V s^?1, which is much higher than that of the controlling reduced graphene oxide film (rGOF, 180.5 F g^?1, 373.6 F cm^?3 and retain only 45.0% of its initial capacitance at 1.0 V s^?1). The cells assembled by the optimal C‐rGOF exhibit maximum energy density of 7.5 Wh kg^?1, power density of 16.9 kW kg^?1, and excellent cycling stability with 91.2% capacitance retention after 21 000 cycles. It is believed that this method can be developed as a useful strategy to prepare rGO‐based materials for energy storage applications.     

Nitrogen and oxygen dual-doped porous carbons prepared from pea protein as electrode materials for high performance supercapacitors

Porous carbons as electrode materials are highly desired for use in energy storage/conversion devices. Herein, the development of a series of highly porous nitrogen and oxygen co-doped carbons by using pea protein (PP) as a cost-effective, sustainable and nitrogen-rich precursor is reported. Pea protein derived carbons (PPDCs) have been prepared by applying a straightforward two-step synthetic route including pyrolysis and KOH-chemical activation. Potassium hydroxide has been employed to generate porosity and introduce oxygen functionalities into the framework of carbon. The heteroatoms doping content and porosity parameters have been tuned by varying the synthesis temperature and activator to precursor ratio. The carbon obtained with optimal synthetic parameters (T = 800 °C and KOH/Precursor = 4) featured the highest surface area, the maximal pore volume and N-/O doping level of 3500 m² g^?1, 1.76 cm³ g^?1, and 2.5-/17.9 at%, respectively. PPDC-4-800 as supercapacitor presented a very high specific capacitance (413 F g^?1 at 1.0 A g^?1 in 1 M KOH), remarkable cycling stability (92% retention after 20000 cycles) and outstanding rate capability (210 F g^?1 at 30 A g^?1). The cooperative effects of the well-developed porous architecture and surface modification of PPDCs resulted in enhanced electrochemical performances, suggesting their potential application for energy storage devices.     

Flexible supercapacitor based on three‐dimensional cellulose/graphite/polyaniline composite

Fast charge‐discharge rate and high areal capacitance, along with high mechanically stability, are the pre‐requisites for flexible supercapacitors to power flexible electronic devices. In this paper, we have used three‐dimensional polyacrylonitrile graphite foam as flexible current collector for electro‐deposition of polyaniline (PANI) nanowires. The graphite foam with PANI was then used to fabricate symmetric supercapacitor. The fabricated supercapacitor in the three‐electrode system shows a high specific capacitance (C_sp) of 357 F.g^?1 and areal capacitance (C_areal) of 7142 mF.cm^?2 in 1 M H₂SO₄ at current density of 80 mA.cm^?2, while using two‐electrode system, it shows C_sp of 256 F.g^?1 and C_areal of 5120 mF.cm^?2 in 1 M H₂SO₄ at current density of 100 mA.cm^?2. The current density of 100 mA.cm^?2 is up to 10 folds higher than reported current densities of many PANI‐based supercapacitors. The high capacitance can be attributed to the spongy network of PANI‐NWs on three‐dimensional graphite surface which provides an easy path for electrolyte ions in active electrode materials. The developed supercapacitor shows specific energy of 64.8 Whkg^?1 and a specific power of 6.1 kWkg^?1 with a marginally decrease of 1.6% in C_sp after 1000^th cycles, along with coulombic efficiency retention of 87% in polyvinyl alcohol/H₂SO₄ gel electrolyte. This flexible supercapacitor exhibits great potential for energy storage application.     

Electrospun zeolitic imidazolate framework‐derived nitrogen‐doped carbon nanofibers with high performance for lithium‐sulfur batteries

Three‐dimensional (3D) nitrogen‐doped carbon nanofibers (N‐CNFs) which were originating from nitrogen‐containing zeolitic imidazolate framework‐8 (ZIF‐8) were obtained by a combined electrospinning/carbonization technique. The pores uniformly distributed in N‐CNFs result in the improvement of electrical conductivity, increasing of BET surface area (142.82 m² g^?1), and high porosity. The as‐synthesized 3D free‐standing N‐CNFs membrane was applied as the current collector and binder free containing Li₂S₆ catholyte for lithium‐sulfur batteries. As a novel composite cathode, the free‐standing N‐CNFs/Li₂S₆ membrane shows more stable electrochemical behavior than the CNFs/Li₂S₆ membrane, exhibiting a high first‐cycle discharge specific capacity of 1175 mAh g^?1at 0.1 C and keeping discharge specific capacity of 702 mAh g^?1 at higher rate. More importantly, as the sulfur mass in cathodes was increased at 7.11 mg, the N‐CNFs/Li₂S₆ membrane delivered 467 mAh g^?1after 150 cycles at 0.2 C. The excellent electrochemical properties of N‐CNFs/Li₂S₆ membrane can be ascribed to synergistic effects of high porosity and nitrogen‐doping in N‐CNFs from carbonized ZIF‐8, illustrating collective effects of physisorption and chemisorption for lithium polysulfides in discharge‐charge processes.     

Flexible sodium‐ion supercapacitor based on polypyrrole/carbon electrode by use of harmless aqueous electrolyte for wearable devices

With the emergence of various wearable devices, supercapacitors have gained immense attention because of their fast response rates. However, most supercapacitors use hazardous electrolyte materials, such as H₂SO₄, KOH, and acetonitrile. Leakage of these types of electrolytes during use would be very harmful to human skin. Therefore, a supercapacitor that does not employ hazardous materials is an attractive option for use in the energy‐storage components of wearable devices. Herein, we successfully demonstrate a Na‐ion supercapacitor (NISC) with a polypyrrole/carbon‐coated heat‐treated carbon felt electrode and an aqueous 0.4 M NaCl electrolyte, which is not harmful. Furthermore, our NISC with polypyrrole/carbon‐coated heat‐treated carbon felt exhibits a high specific capacitance (31.09 F g^?1) and a fast response rate (chargeable at 0.5‐s intervals). The proposed NISC with no harmful materials in the electrolyte has an excellent response rate. It will establish useful guidelines for the energy‐storage components in wearable devices Copyright © 2017 John Wiley & Sons, Ltd.     

Novel sustainable nitrogen,iodine-dual-doped hierarchical porous activated carbon as a superior host material for high performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries exhibit great potential for next-generation high energy density energy storage. However, the insulativity of sulfur and the “shuttle effect” of polysulfides result in low utilization efficiency of active sulfur, fast capacity decay and inferior cycling stability, which pose the key challenge to their practical applications. Herein, a N, I-dual-doped hierarchical porous activated carbon (NIWFC) is successfully prepared for advanced Li-S batteries by the simple one-pot pyrolysis and hydrothermal processes. The obtained NIWFC owns interconnected porous framework with desirable specific surface area (2088.56 m² g^?1) and large volume space (1.106 cm³ g^?1), which can accommodate high content of active sulfur and immobilize polysulfides through physical confinement. Moreover, the existence of N and I heteroatoms could effectively strengthen the chemical adsorption to polysulfides and create more active sites to enhance sulfur utilization. Attributed to these merits, impregnating sulfur into NIWFC (NIWFC/S) as cathode of Li-S batteries achieves a high initial discharge capacity of 1284.1 mAh g^?1 at 0.1 C (remaining at 916.7 mAh g^?1 after 100 cycles) and the outstanding cycling stability with a low capacity fading rate of 0.061% per cycle over 350 cycles at 1.0 C. This work provides a facile and cost-effective strategy to design a novel sustainable N, I-dual-doped porous carbon for high performance Li-S batteries and various energy storage fields.     

Sodium alginate assisted preparation of oxygen-doped microporous carbons with enhanced electrochemical energy storage and hydrogen uptake

Microporous carbons with large oxygen content have been successful synthesized from biomass by the sodium alginate assisted strategy. During the activation process, the Na₂O formed by the decomposition of sodium alginate combines with the activator KOH to undergo a redox reaction in situ with precursor, thereby forming a rich porosity in the samples. The obtained samples possess not only high SSA (2310~3001 m² g^?1) and large pore volume (0.89~1.19 cm³ g^?1) arising almost completely (>90%) from micropores, but also retains a high content of oxygen (21.86~32.47 wt %). As supercapacitor electrodes, the oxygen-doped microporous carbons display a high specific capacitance of 385 F g^?1 at 0.5 A g^?1 with capacity stability of 91.5% after 20 000 cycles at 5 A g^?1. As hydrogen storage materials, the oxygen-doped microporous carbons exhibit enhanced hydrogen storage capacity of 2.84 wt% (77 K, 1 bar) and 0.91 wt% (303 K, 50 bar). Experimental data indicate that this work provides a simple-efficient and universal strategy for preparing oxygen-doped microporous carbon for high-performance energy and hydrogen storage.     

N,P, S co-doped biomass-derived hierarchical porous carbon through simple phosphoric acid-assisted activation for high-performance electrochemical energy storage

Porous carbon materials are the most widely used electrode materials in Electric Double Layer Supercapacitor (EDLS). Optimize specific surface area, improving hierarchical pores structure, and doping heteroatoms are all important methods to improve the capacitance performance of electrodes. Herein, we synthesize walnut shell-derived hierarchical porous carbon (WSPC) with cost-effective and well-developed pore for electrochemical energy storage via simple phosphoric acid-assisted activation method. The final porous carbon products have perfect microporous structure, abundant heteroatom functional groups (the atomic content ratio of nitrogen, phosphorus and sulfur reaches 10.3%), and high specific surface area and pore volume (up to 2583 m² g^?1 and 1.236 cm³ g^?1, respectively). In the three-system, the electrode shows an optimal specific capacitance of up to 332 F g^?1 and excellent rate performance. In the symmetric system, the symmetric device WSPC//WSPC shows a maximum gravimetric specific energy of ~14.08 Wh kg^?1. And the device still has a specific energy of 9.75 Wh kg^?1 even under the high gravimetric specific power of 7 kW kg^?1. In addition, the device has excellent cycle stability and retains an initial specific capacitance of 90.2% after 8000 galvanostatic charge-discharge (GCD) cycle. In summary, these outstanding results suggest the biomass derived porous carbon possessing the potential and will show great commercial value for the fabrication of high performance supercapacitors.     

All‐carbon hybrids for high performance supercapacitors

A hybrid nanostructure with partially reduced graphene oxide (rGO) and carbon nanofibers (CNFs) was fabricated and used as supercapacitor electrodes. A straightforward, environmentally friendly, and low‐cost microwave‐assisted reduction process was developed for the synthesis of rGO/CNF hybrid structures. The fabricated supercapacitor devices showed a specific capacitance of 95.3 F g^?1 and a superior long‐term cycling stability. A capacitance retention of more than 97% after 11 000 galvanostatic charge discharge cycles was obtained. These and other results reported in this paper indicate that high‐rate, all‐carbon, rGO/CNF hybrid nanostructures are highly promising supercapacitor electrode materials.     

Three-dimensional nitrogen rich bubbled porous carbon sponge for supercapacitor & pressure sensing applications

Three-dimensional (3D) porous carbonaceous materials offer numerous merits such as light-weight, high surface area, flexibility, and thus hold immense potential in energy storage applications. In this work, we report preparation of nitrogen-rich free-standing compressible porous neuron-like carbon sponge using commercially available kitchen sponge by a facile, cost-effective, and scalable synthetic strategy. The unique neuron-like bubbled interconnected carbon structure with enhanced N/O functionalities improves the electrochemical performance by providing sufficient space for ion transport and large accessible surface-active sites. This material also delivers high current response under compressive stress acting as a pressure sensor. This bubbled carbon material achieves an improved specific capacitance of 268.5 F g⁻¹ at 0.5 A g⁻¹. As a self-supporting electrode in a symmetrical supercapacitor cell, it still delivers a good specific capacitance of 167 F g⁻¹ at 0.35 A g⁻¹, retaining 92.5% of capacitance over 7000 charge/discharge cycles. Furthermore, the device delivers a maximum energy density of 14.8 Wh Kg⁻¹, demonstrating its immense potential for multi-functional applications owing to its unique features.     

Controlled synthesis of MnO2/CNT nanocomposites for supercapacitor applications

Abstract

In this work, manganese oxide (MnO₂)/carbon nanotube (CNT) nanocomposites have been prepared as electrode materials for supercapacitor applications. The materials were synthesised using a traditional and facile chemical deposition method. Effects from CNT amounts, synthesis time, pH value and CNT treatment using nitric acid have been thoroughly investigated. It was found that the sample synthesised for 3 h at pH 5 had achieved the best performance with a specific capacitance of 115 F g^?1 at a discharge rate of 0·5 A g^?1. A capacitance retention of 95% after 1000 cycles has been observed for the sample synthesised in the neutral environment. We believe that findings from this work will pave a road for nanostructured MnO₂/CNT composites with better performance in energy storage applications.     

Oxygen‐modified multiwalled carbon nanotubes: physicochemical properties and capacitor functionality

Multiwalled carbon nanotubes (MWCNTs) have found numerous applications in energy conversion systems. The current work focused on the introduction of oxygen moieties onto the walls of MWCNTs by five different reagents and investigating the associated physicochemical properties. Oxygen‐containing groups were introduced onto MWCNTs using an ultrasound water‐bath treatment with HNO₃, HCl, H₂O₂ or HCl/HNO₃ solution. Physicochemical properties were characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman, thermal gravimetric analysis, textural characteristics, cyclic voltammetry and electrochemical impedance spectroscopy. The study focus was mainly on linking the physicochemical properties of oxygen‐functionalised MWCNTs and suitability in electrochemical capacitors using group one sulfates. From the Fourier transform infrared spectroscopy KBr pellet protocol, peaks at 3400, 2370 and 1170 cm^?1 suggest oxygen‐containing functionalities on MWCNTs. HNO₃ treatment introduced highest oxygen‐containing moieties and achieved highest specific capacitance in Li₂SO₄ and Na₂SO₄ electrolytes of 36.200 F g^?1 (77 times better than pristine) and 45.100 F g^?1 (2.5 times enhancement), respectively. For K₂SO₄, it was 33.600 F g^?1 (4.9 times better) with HNO₃/HCl‐treated samples. Oxygen‐functionalised MWCNTs displayed both pseudo and electrochemical double‐layer mechanism of enhanced charge storage and cycle stability in group one sulfates electrolytes. The dominating charge storage mechanism was pseudo, and Na₂SO₄ was the best electrolyte amongst the three group one sulfates investigated. Copyright © 2017 John Wiley & Sons, Ltd.     

Composite of manganese dioxide impregnated in porous hollow carbon spheres for flexible asymmetric solid‐state supercapacitors

Compared with symmetric supercapacitors, asymmetric supercapacitors are been widely applied in energy storage devices because of delivering an impressible energy density. Herein, a simple temple strategy was used to fabricate the porous hollow carbon spheres (PHCS) with high specific surface area of 793 m² g^?1, large pore volume of 1.0 cm³ g^?1 and pore size distribution from micropores to mesopores, serving as the capacitive electrodes of asymmetric supercapacitors. Subsequently, manganese dioxide (MnO₂) was impregnated into the PHCS to form a faradic electrode with a promising performance, owing to a synergistic effect between high capacity MnO₂ and conductive PHCS. Furthermore, the flexible asymmetric solid‐state devices were constructed with PHCS anode, PHCS@MnO₂ cathode, and PVA/LiCl electrolyte, extending a voltage window up to 1.8 V. The extensive voltage window would lead to an increased energy density. In our case, the flexible asymmetric sandwich exhibit excellent electrochemical performance in terms of a high energy density capacity of 26.5 W·h kg^?1 (900 W kg^?1) and superior cycling performance (10 000 cycles). Therefore, the developed strategy provides a strategy to achieve the PHCS‐based composites for the application in the asymmetric solid‐state supercapacitors, which will enable a widely field of flexible energy storage devices.     

Niobium carbide/reduced graphene oxide hybrid porous aerogel as high capacity and long‐life anode material for Li‐ion batteries

Two‐dimensional material MXenes owing to their hydrophilic nature, surface termination, and high conductivity can be used in the energy storage device as an anode material. However, poor ion transfer and less available intercalating sites due to self‐stacking of MXene sheets prevent comprehensive utilization of their electrochemical properties. To resolve this problem, a facile method is introduced in this paper to disperse MXene sheets onto reduced graphene oxide sheets to form a porous structure by enhancing electrostatic interactions between two components, which can facilitate ion movement and provide access of ions to more intercalating sites. This hybrid material delivered a capacity of 357 mAh g^?1 at 0.05 A g^?1 as anode in case of lithium‐ion batteries. Furthermore, the hybrid material showed exceptional stability even after 1000 cycles at 1 A g^?1. Current work offers an easy approach for the synthesis of high‐performance niobium carbide‐based hybrid energy storage materials.     

Novel inorganic binary mixture for low‐temperature heat storage applications

In this study, an inorganic mixture based on bischofite (industrial by‐product) was developed and characterized for its application as a phase change material for low‐temperature thermal energy storage. The most appropriate composition was established as 40 wt% bischofite and 60 wt% Mg(NO₃)₂ · 6H₂O. Thermophysical properties were defined and compared with those of the mixture with synthetic MgCl₂ · 6H₂O. The heat of fusion and melting temperature were measured as 62.0°C and 132.5 kJ kg^?1 for the mixture with MgCl₂ · 6H₂O and 58.2°C and 116.9 kJ kg^?1 for the mixture with bischofite. The specific heat capacity values, cycling, and thermal stability for both mixtures were also determined. For the mixture with MgCl₂ · 6H₂O, the densities of the solid and liquid states were 1517 kg m^?3 (ambient temperature) and 1515 kg m^?3 (at 60‐70°C), respectively. For the mixture with bischofite, the densities of the solid and liquid states were 1525 kg m^?3 (ambient temperature) and 1535 kg m^?3 (at 60‐70°C), respectively. Both mixtures show supercooling of about 23.4 and 34.1°C for the mixture with bischofite and MgCl₂ · 6H₂O, respectively. In addition, it was shown that supercooling may be reduced by increasing the quantity of material tested. Thereby, it was established that an inorganic mixture based on bischofite is a promising PCM for low‐temperature thermal energy storage applications.