Storage Devices Research Articles

Anionic Hofmeister Effect Regulated Conductivity in Polyelectrolyte Hydrogels for High-Performance Supercapacitor.

The Hofmeister effect not only affects the stability and solubility of protein colloids but also has specific effects on the polymer molecules. Here, the impact of the Hofmeister effect on the electrochemical properties of polyelectrolyte hydrogels at room temperature and subzero temperature studied for the first time. Polyelectrolyte hydrogels exhibit an anti-polyelectrolyte effect in low concentrations of ammonium salt, while they exhibit an obvious Hofmeister effect in high concentrations of ammonium salt. Kosmotropic ions demonstrate strong interaction with water molecules or polymer chains, resulting in the reduction of conductivity of polyelectrolyte hydrogels. However, chaotropic ions exhibit weak interactions with water molecules or molecular chains, leading to an increase in conductivity. The Hofmeister effect has a more significant effect on the polyzwitterion electrolyte. The conductivity of polyzwitterion hydrogel soaked in chaotropic ion is up to 6.2 mS cm-1 at -40°C. The supercapacitor assembled by polyzwitterion electrolytes maintains a capacitance retention rate of 85% and ≈100% coulomb efficiency after 15 000 cycles at -40°C. This study elucidates the influence of the Hofmeister effect on conductivity in polyelectrolytes and expands the regulatory approach for improving the performance of energy storage devices.

In Situ Polymerization of a Self-Healing Polyacrylamide-Based Eutectogel as an Electrolyte for Zinc-Ion Batteries.

Gel electrolytes have attracted extensive attention in flexible batteries. However, the traditional hydrogel electrolyte is not enough to solve the fundamental problems of zinc anodes, such as dendrite growth, side reactions, and freezing failure at temperatures below zero, which seriously restricts the development of zinc-ion batteries. As a flexible energy storage device, the zinc-ion battery inevitably undergoes multiple stretches, bends, folds, or twists in daily use. Here, a self-healing and stretchable eutectogel, designated as deep eutectic solvent-acrylamide eutectic gel (DA-ETG), was developed as a solid-state electrolyte for zinc-ion batteries. This gel was prepared by immobilizing a high-concentration ZnCl2 deep eutectic solvent (DES) into a polyacrylamide matrix through in situ polymerization under ultraviolet light. The eutectogel electrolyte showed exceptional mechanical properties with a maximum fracture strength of 0.6 MPa and a high ionic conductivity of 6.4 × 10-4 S cm-1. The in situ polymerization of the DA-ETG electrolyte in the assembly of a full solid-state zinc-ion battery increased the electrode-electrolyte interface area contact, reduced the ion transport distance between the electrode and electrolyte, minimized the internal resistance, and enhanced the battery's long-term cycling stability. Using the DA-ETG electrolyte, a remarkably high capacity of 580 mAh g-1 at 0.1 A g-1 was achieved by the zinc-ion battery, and a considerable capacity of 234 mAh g-1 was maintained even at 5 A g-1, showing exceptional rate performance. After 2000 cycles at 2 A g-1, the cell with the eutectogel retained a capacity of 85% with a cycling efficiency close to 98%, which demonstrated excellent cycling stability. The self-healing function enabled the prepared soft battery to be reused multiple times, with full contact between the electrode and electrolyte interface, and without device failures.

High-Performance Organic-Inorganic Hybrid Conductive Hydrogels for Stretchable Elastic All-Hydrogel Supercapacitors and Flexible Self-Powered Integrated Systems.

Conductive polymer hydrogels exhibit unique electrical, electrochemical, and mechanical properties, making them highly competitive electrode materials for stretchable high-capacity energy storage devices for cutting-edge wearable electronics. However, it remains extremely challenging to simultaneously achieve large mechanical stretchability, high electrical conductivity, and excellent electrochemical properties in conductive polymer hydrogels because introducing soft insulating networks for improving stretchability inevitably deteriorates the connectivity of rigid conductive domain and decreases the conductivity and electrochemical activity. This work proposes a distinct confinement self-assembly and multiple crosslinking strategy to develop a new type of organic-inorganic hybrid conductive hydrogels with biphase interpenetrating cross-linked networks. The hydrogels simultaneously exhibit high conductivity (2000 S m-1), large stretchability (200%), and high electrochemical activity, outperforming existing conductive hydrogels. The inherent mechanisms for the unparalleled comprehensive performances are thoroughly investigated. Elastic all-hydrogel supercapacitors are prepared based on the hydrogels, showing high specific capacitance (212.5 mF cm-2), excellent energy density (18.89 µWh cm-2), and large deformability. Moreover, flexible self-powered luminescent integrated systems are constructed based on the supercapacitors, which can spontaneously shine anytime and anywhere without extra power. This work provides new insights and feasible avenues for developing high-performance stretchable electrode materials and energy storage devices for wearable electronics.

Construction of V2O5@MXene Cathodes toward a High Specific Capacity Aqueous Aluminum-Ion Battery.

Aqueous aluminum-ion batteries (AAIBs) are considered a strong candidate for the new generation of energy storage devices. The lack of suitable cathode materials has been a bottleneck factor hindering the future development of AAIBs. In this work, we design and construct a highly effective cathode with dual morphologies. Two-dimensional (2D) layered MXene materials possessed good conductivity and hydrophilicity, which are used as the substrates to deposit rod-shaped vanadium oxides (V2O5) to form a three-dimensional (3D) cathode. The cathode design provides a strong boost for the rapid electrochemical activities of rod-shaped V2O5 by embedding/extracting both protons (H+) and aluminum-ion (Al3+). As a result, the V2O5@MXene cathode based AAIB delivers an ultrahigh initial specific capacity of 626 mAh/g at 0.1 A/g with a stable cycle performance up to 100 cycles. This work is a breakthrough for the development of cathode materials for AAIBs.

Self-regulating thermal energy storage device

Self-regulating thermal energy storage device

A Novel Hydrated Iron Vanadate Cathode Material for Advanced Aqueous Nickel-Ion Batteries.

Aqueous nickel-ion batteries (ANIBs) as an emerging energy storage device attracted much attention owing to their multielectron redox reaction and dendrite-free Ni anode, yet their development is hindered by the divalent properties of Ni2+ and the lack of suitable cathode materials. Herein, a hydrated iron vanadate (Fe2V3O10.5∙1.5H2O, FOH) with a preferred orientation along the (200) plane is innovatively proposed and used as cathode material for ANIBs. The FOH cathode exhibits a remarkable capacity of 129.3 mAh g-1 at 50mA g-1 and a super-high capacity retention of 95% at 500mA g-1 after 700 cycles. The desirable Ni2+ storage capacity of FOH can be attributed to the preferentially oriented and tunnel structures, which offer abundant reaction active planes and a broad Ni2+ diffusion path, the abundant vacancies and high specific surface area further increase ion storage sites and accelerate ion diffusion in the FOH lattice. Furthermore, the Ni2+ storage mechanism and structural evolution in the FOH cathode are explored through ex situ XRD, ex situ Raman, ex situ XPS and other ex situ characteristics. This work opens a new way for designing novel cathode materials to promote the development of ANIBs.

All-protonic fuel cell designs and developments fuelled by ammonia.

Ammonia is a gas that produces zero carbon emissions when used in energy storage systems. Hence, there is increasing interest for the application of ammonia as fuel in various energy storage devices, specifically solid oxide fuel cells (SOFCs), as it has the potential to be efficient and environmentally friendly. In addition, compared to other fuel cells, SOFCs fed with ammonia offer various benefits such as such as sustainability and safety. This review compares and contrasts the opportunities and challenges of ammonia fuel cell technologies and helps to analyze their working principles. The main goal of this review is to investigate the viability of an "all-protonic" fuel cell using ammonia fuel while also highlighting the key challenges and limitations of implementing such technology.

Hierarchical porous carbon derived from petroleum coke via one-step chemical activation for the fabrication of a supercapacitor and real time clock application.

The escalating demand for energy requires highly efficient energy storage devices and advanced materials. Low-cost carbon resources and their derivatives have always been a topical research area. Petroleum coke is an abundant and affordable resource that contributes to the scalability and cost effectiveness of carbon materials. Porous carbon derivatives have acquired great attention for energy storage and conversion owing to their large surface area, environmental friendliness, exceptional electrical conductivity, and economic viability. Thus, in this work, we directly synthesized hierarchical porous carbon materials from oil refinery petroleum coke (pet-coke) using a single-step KOH activation method to utilize them for the fabrication of a coin cell supercapacitor for electronic application. The synthesized pet-coke based porous carbon shows a high specific surface area (1108 m2 g-1) and excellent porosity. After conducting extensive electrochemical analysis, it shows promising specific capacitances of 170 and 70 F g-1 in aqueous and organic electrolytes, respectively. Further, a coin cell supercapacitor was fabricated using the pet-coke derived porous carbon in an organic electrolyte with a potential window of 2.7 V, demonstrating superior rate capability and durability. The calculated energy and power density of the fabricated coin cell indicate its favorable supercapacitor application to act as a backup power source for real time clock (RTC) application in electronics.

Optimal design of a combined Power-Heating-Oxygen system for plateau hotel buildings

The Qinghai–Tibet Plateau of China is a region of low atmospheric pressure and oxygen deficiency, with a high heating demand in the winter; therefore, plateau hotel buildings have a demand for comprehensive power-heating-oxygen loads. Solar energy resources are particularly abundant in plateau areas, where a combined multi-energy system based on solar energy can be designed to meet the demand of plateau hotel buildings for multiple loads. However, currently, there is a relative lack of methods for the optimal design and performance evaluation of combined power-heating-oxygen (CPHO) systems. Thus, this study proposes a CPHO system model for plateau hotels, and provides two operation strategies, i.e., power priority and oxygen priority. Taking the minimum total annual cost of the combined system as the optimization objective, an optimized CPHO system model for plateau hotels has been proposed, followed by a case study of a hotel in Qilian County, Qinghai Province. Results showed that: 1) Compared with the conventional combined power-heating (CCPH) system, the CPHO system saw reductions of 0.8% and 1.3% in its total annual cost under the operation strategies of power priority and oxygen priority, respectively. 2) The energy self-consumption (SC) rates of the CCPH system and CPHO system under the operation strategies of power priority and oxygen priority were 84.8%, 64.2%, and 89.8%, respectively; with power self-sufficiency (PSS) rates of 8.3%, 49.9%, and 29.5%, and oxygen self-sufficiency (OSS) rates of 0.0%, 3.2%, and 4.7%, respectively. 3) The total annual cost of the CPHO system was affected slightly by the cost of photovoltaics (PVs) and energy storage devices, and significantly by the price of oxygen. When the price of oxygen was 8 yuan per normal cubic meter(Nm3) or above, the CPHO system was economically efficient under the operation strategy of oxygen priority. When the price of oxygen was 10yuan/Nm3 or above, the system was economically efficient under both operation strategies.

Off-Stoichiometry of Sodium Iron Pyrophosphate as Cathode Materials for Sodium-Ion Batteries with Superior Cycling Stability.

As one of the important devices for large-scale electrochemical energy storage, sodium-ion batteries have received much attention due to the abundant resources of raw materials. However, whether it is a base station power source, an energy storage power station, or a start-stop power supply, long energy cycle life (more than 5000 cycles), high stability, and safety performance are application prerequisites. Regrettably, currently, few sodium-ion batteries can meet this requirement, mainly due to shortcomings in positive electrode performance. We report a sufficiently stable sodium-ion battery cathode material, Na2Fe0.95P2O7, that retains 97.5% capacity after 5000 charge/discharge cycles. The use of nonstoichiometry in the lattice enables simultaneous modification of the crystal and electronic structure, promoting Na2Fe0.95P2O7 to be extremely stable while still being able to achieve a capacity of 92 mAh g-1 and stable cycling at high temperatures up to 60 °C. Our results confirm the positive effect of nonstoichiometric ratios on the performance of Na2Fe0.95P2O7 and provide a reliable idea to promote the practical application of sodium-ion batteries.

Fluorinated Linkers Enable High-Voltage Pyrrolidinium-based Dicationic Ionic Liquid Electrolytes.

Novel fluorinated, pyrrolidinium-based dicationic ionic liquids (FDILs) as high-performance electrolytes in energy storage devices have been prepared, displaying unprecedented electrochemical stabilities (up to 7 V); thermal stability (up to 370 °C) and ion transport (up to 1.45 mS cm‑1). FDILs were designed with a fluorinated ether linker and paired with TFSI/FSI counterions. To comprehensively asess the impact of the fluorinated spacer on their electrochemical, thermal, and physico-chemical properties, a comparison with their non-fluorinated counterparts was conducted. With a specific focus on their application as electrolytes in next-generation high-voltage lithium-ion batteries, the impact of the Li-salt on the characteristics of dicationic ILs was systematically evaluated. The incorporation of a fluorinated linker demonstrates significantly superior properties compared to their non-fluorinated counterparts, presenting a promising alternative towards next-generation high-voltage energy storage systems.

Thermally stable modification of PEO‐based all‐solid‐state electrolytes via a stretching flow field: Constructing a supportive polymer skeleton

AbstractSince the advent of all‐solid‐state lithium‐ion batteries (ASSLIBs), they have been widely regarded as the ideal high‐temperature‐resistant energy storage devices. The solid‐state electrolyte, a crucial component, should possess high ionic conductivity, excellent flexibility, and significant mechanical strength. Poly(ethylene oxide)‐based all‐solid‐state polymer electrolytes (PEO‐ASSPE) appear to meet these criteria. However, PEO‐ASSPE exhibits poor stability at elevated temperatures, where localized overheating and internal thermal runaway can lead to battery short‐circuit failure. To address these issues, this study employs a ethylene‐methacrylic acid copolymer (EMAA) as a structural support polymer, blended via a eccentric rotor mixer. The homogeneously dispersed EMAA within the PEO matrix forms an interpenetrating network structure and interacts with other components, significantly enhancing the high‐temperature electrochemical stability of the composite polymer electrolytes (CPEs) while maintaining ionic conductivity. Research has demonstrated that when the EMAA content is 40 wt.%, the resulting CPE‐40EMAA exhibit high ionic conductivity (4.07 × 10−4 S cm−1), a high lithium‐ion transference number (0.564), a broad electrochemical stability window (5.1 V), and excellent high‐temperature lithium metal cycling stability (stable cycling for 800 h at current density of 0.1 mA cm−2), which sufficiently meets the electrochemical performance requirements for ASSPEs in high‐temperature energy storage batteries.

Suppressed Dissolution of Fluorine-Rich SEI Enables Highly Reversible Zinc Metal Anode for Stable Aqueous Zinc-Ion Batteries.

The instability of the solid electrolyte interface (SEI) is a critical challenge for the zinc metal anodes, leading to an erratic electrode/electrolyte interface and hydrogen evolution reaction (HER), ultimately resulting in anode failure. This study uncovers that the fluorine species dissolution is the root cause of SEI instability. To effectively suppress the F- dissolution, an introduction of a low-polarity molecule, 1,4-thioxane (TX), is proposed, which reinforces the stability of the fluorine-rich SEI. Moreover, the TX molecule has a strong affinity for coordinating with Zn2+ and adsorbing at the electrode/electrolyte interface, thereby diminishing the activity of local water and consequently impeding SEI dissolution. The robust fluorine-rich SEI layer promotes the high durability of the zinc anode in repeated plating/stripping cycles, while concurrently suppressing HER and enhancing Coulombic efficiency. Notably, the symmetric cell with TX demonstrates exceptional electrochemical performance, sustaining over 500 hours at 20 mA cm-2 with 10 mAh cm-2. Furthermore, the Zn||KVOH full cell exhibits excellent capacity retention, averaging 6.8 mAh cm-2 with 98 % retention after 400 cycles, even at high loading with a lean electrolyte. This work offers a novel perspective on SEI dissolution as a key factor in anode failure, providing valuable insights for the electrolyte design in energy storage devices.

Suppressed Dissolution of Fluorine‐Rich SEI Enables Highly Reversible Zinc Metal Anode for Stable Aqueous Zinc‐Ion Batteries

AbstractThe instability of the solid electrolyte interface (SEI) is a critical challenge for the zinc metal anodes, leading to an erratic electrode/electrolyte interface and hydrogen evolution reaction (HER), ultimately resulting in anode failure. This study uncovers that the fluorine species dissolution is the root cause of SEI instability. To effectively suppress the F− dissolution, an introduction of a low‐polarity molecule, 1,4‐thioxane (TX), is proposed, which reinforces the stability of the fluorine‐rich SEI. Moreover, the TX molecule has a strong affinity for coordinating with Zn2+ and adsorbing at the electrode/electrolyte interface, thereby diminishing the activity of local water and consequently impeding SEI dissolution. The robust fluorine‐rich SEI layer promotes the high durability of the zinc anode in repeated plating/stripping cycles, while concurrently suppressing HER and enhancing Coulombic efficiency. Notably, the symmetric cell with TX demonstrates exceptional electrochemical performance, sustaining over 500 hours at 20 mA cm−2 with 10 mAh cm−2. Furthermore, the Zn||KVOH full cell exhibits excellent capacity retention, averaging 6.8 mAh cm−2 with 98 % retention after 400 cycles, even at high loading with a lean electrolyte. This work offers a novel perspective on SEI dissolution as a key factor in anode failure, providing valuable insights for the electrolyte design in energy storage devices.

Anionic Chemistry Modulation Enabled Environmental Self‐Charging Aqueous Zinc Batteries: The Case of Carbonate Ions

Anionic chemistry modulation represents a promising avenue to enhance the electrochemical performance and unlock versatile applications in cutting‐edge energy storage devices. Herein, we propose a methodology that involves anionic chemistry of carbonate anions to tailor the electrochemical oxidation‐reduction reactions of bismuth (Bi) electrodes, where the conversion energy barrier for Bi (0) to Bi (III) has been significantly reduced, endowing anionic full batteries with enhanced electrochemical kinetics and chemical self‐charging property. The elaborately designed batteries with an air‐switch demonstrate rapid self‐recharging capabilities, recovering over 80% of the electrochemical full charging capacity within a remarkably short timeframe of 1 hour and achieving a cumulative self‐charging capacity of 5 Ah g‐1. The aqueous self‐charging battery strategy induced by carbonate anion, as proposed in this study, holds the potential for extending to various anionic systems, including seawater‐based Cl− ion batteries. This work offers a universal framework for advancing next‐generation multi‐functional power sources.

Electrochemical Investigation of ZnS/NiO Nanocomposite based Symmetric Supercapattery

AbstractSupercapattery is an ideal energy storage device combining the features of supercapacitors and batteries, offers a high‐energy density as well as high‐power density with extended operational lifespan. In this work, zinc sulfide (ZnS) and zinc sulfide/nickel oxide (ZnS/NiO) nanocomposite was synthesized via chemical coprecipitation method and characterized using state‐of‐the‐art analytical tools. The ZnS/NiO electrode exhibited remarkable electrochemical performance as an electrode material than pure ZnS. The ZnS/NiO nanocomposite exhibited high crystallinity, and spherical nanoparticles with an average grain size of 20–40 nm having a homogeneous dispersion. The ZnS/NiO electrode exhibited an ultrahigh specific capacity of 1803.87 Cg−1 at a relatively low scan rate of 10 mVs−1 in a 1 M KOH solution from cyclic voltammetry and 393 Cg−1 at 16 Ag−1 from charge discharge measurements, and it showed exceptional cycling stability (98 % capacity retention after 1000 cycles). Furthermore, the ZnS/NiO symmetric supercapattery device exhibited 44.43 Fg−1 specific capacitance, 5.52 Wh kg−1 energy density, and 1600 Wkg−1 power density at current density of 0.8 Ag−1 in 1 M KOH solution from galvanostatic charge discharge. After 3000 cycles, the ZnS/NiO nanomaterial demonstrated promising cyclic stability of 95 %. The ZnS/NiO supercapattery nanocomposite might be considered as a potential hybrid electrode material for the future development of electrochemical energy storage devices.

Structural, Morphological and Ferroelectric Properties of Sr-Cd Co-Doped Nickel Ferrite for Energy Storage Devices

Ferroelectric materials, renowned for their capacity to demonstrate spontaneous electric polarization reversible through an external electric field, are essential in numerous technological applications owing to their distinctive characteristics. For this, a series of spinel Sr-Cd co-doped nickel ferrite nanomaterials Cd0.5−xSrxNi0.5Fe2O4 (x = 0.0, 0.1, 0.2 and 0.3) were prepared through the standard sol-gel auto combustion method The XRD patterns showed that the prepared samples have a cubic spinel structure. The crystallite sizes of the samples vary from 29 to 40 nm. The morphology of prepared samples showed uniformly distributed spheres. Magnetic properties showed the soft magnetic nature of the prepared ferrites. The ferroelectric study revealed that Sr-Cd substituted ferrites exhibited the elliptical nature of ferroelectric loops at normal room temperature. The maximum polarization has been achieved at x = 0.3. The understanding of current and voltage (I–V) showed a slowly decreasing tendency of leakage current on both sides symmetrically against the increasing Sr content. The conductivity of the prepared spinel increases as a function of higher Sr doping. The real part of dielectric constant increases with increasing frequency. The materials show large elliptical loops indicating high asymmetric ferroelectric energy storage capability.

Anionic Chemistry Modulation Enabled Environmental Self-Charging Aqueous Zinc Batteries: The Case of Carbonate Ions.

Anionic chemistry modulation represents a promising avenue to enhance the electrochemical performance and unlock versatile applications in cutting-edge energy storage devices. Herein, we propose a methodology that involves anionic chemistry of carbonate anions to tailor the electrochemical oxidation-reduction reactions of bismuth (Bi) electrodes, where the conversion energy barrier for Bi (0) to Bi (III) has been significantly reduced, endowing anionic full batteries with enhanced electrochemical kinetics and chemical self-charging property. The elaborately designed batteries with an air-switch demonstrate rapid self-recharging capabilities, recovering over 80% of the electrochemical full charging capacity within a remarkably short timeframe of 1 hour and achieving a cumulative self-charging capacity of 5 Ah g-1. The aqueous self-charging battery strategy induced by carbonate anion, as proposed in this study, holds the potential for extending to various anionic systems, including seawater-based Cl- ion batteries. This work offers a universal framework for advancing next-generation multi-functional power sources.

Boron Nitride‐Integrated Lithium Batteries: Exploring Innovations in Longevity and Performance

The current global warming, coupled with the growing demand for energy in our daily lives, necessitates the development of more efficient and reliable energy storage devices. Lithium batteries (LBs) are at the forefront of emerging power sources addressing these challenges. Recent studies have shown that integrating hexagonal boron nitride (h‐BN) nanomaterials into LBs enhances the safety, longevity, and electrochemical performance of all LB components, including electrodes, electrolytes, and separators, thereby suggesting their potential value in advancing eco‐friendly energy solutions. This review provides an overview of the most recent applications of h‐BN nanomaterials in LBs. It begins with an informative introduction to h‐BN nanomaterials and their relevant properties in the context of LB applications. Subsequently, it addresses the challenges posed by h‐BN and discusses existing strategies to overcome these limitations, offering valuable insights into the potential of BN nanomaterials. The review then proceeds to outline the functions of h‐BN in LB components, emphasizing the molecular‐level mechanisms responsible for performance improvements. Finally, the review concludes by presenting the current challenges and prospects of integrating h‐BN nanomaterials into battery research.

Stabilization and Control of Weakly Correlated Polar Skyrmions in Ferroelectric Thin Films

In recent years, polar topological textures like skyrmions and vortices in ferroelectric superlattices and multilayers have received extensive attention. However, the polar topological textures in these systems suffer strong interactions and are difficult to be manipulated as individual elements, limiting their application prospects in storage and logic devices. Here, via phase field simulations, we demonstrate domain engineering as a feasible strategy to create diverse weakly correlated polar topological texture arrays in single-layer tetragonal ferroelectric thin films, including Néel-type skyrmions with positive/negative topological charges and Bloch-type skyrmions with different chirality. We calculate the stability phase diagram and reveal the evolution characteristics of these polar topological textures under local electric and mechanical stimuli. We realize local erasing and writing of single Néel- and Bloch-type skyrmions, as well as deterministic chirality control of single Bloch-type skyrmion, confirming the weak correlation of the polar skyrmions. Our study therefore demonstrates domain engineering as an effective strategy for stabilizing weakly correlated polar topological textures, which extends the existence system of polar topological textures and paves a new way for the design of storage and logic devices based on polar topological textures.