Mass Loading Of Active Materials Research Articles

High‐Entropy Electrolyte Driven by Multi‐Solvation Structures for Long‐Lifespan Aqueous Zinc Metal Pouch Cells

Aqueous zinc metal batteries (AZMBs) are promising for grid‐scale energy storage due to their low cost and high safety. However, poor stability and an unfavorable freezing point hinder their actual application. Herein, a ternary salts‐based high‐entropy electrolyte (HEE) composed of Zn0.2Na0.4Li0.4(ClO4)1.2·7H2O is proposed to address the above issues. The addition of perchlorate salts with different cations reduces the size of ion clusters, significantly increases the solvation structure species, and promotes the anion‐rich Zn2+ solvation structures, resulting in an enlarged electrochemical stability window, favorable viscosity and ionic conductivity, and low freezing point. Furthermore, characterization and calculations confirm that multiple types of solvation structures effectively increase the electrolyte entropy. As a consequence, the Zn/Zn symmetric cells in HEE can sustainably cycle for at least 1000 hours and 1500 hours under room and subzero temperatures, respectively. The Na0.33V2O5/Zn and polyaniline/Zn full cells can even last for 30000 and 20000 cycles without capacity decay at −20 °C, respectively. The pouch cells employing HEE deliver promising capacity and stability, even at high mass loading of active materials. This strategy of introducing multiple salts with different cations to construct a high‐entropy environment provides a facile approach for high‐performance and long‐lifespan AZMBs across a wide temperature range.

High-Entropy Electrolyte Driven by Multi-Solvation Structures for Long-Lifespan Aqueous Zinc Metal Pouch Cells.

Aqueous zinc metal batteries (AZMBs) are promising for grid-scale energy storage due to their low cost and high safety. However, poor stability and an unfavorable freezing point hinder their actual application. Herein, a ternary salts-based high-entropy electrolyte (HEE) composed of Zn0.2Na0.4Li0.4(ClO4)1.2·7H2O is proposed to address the above issues. The addition of perchlorate salts with different cations reduces the size of ion clusters, significantly increases the solvation structure species, and promotes the anion-rich Zn2+ solvation structures, resulting in an enlarged electrochemical stability window, favorable viscosity and ionic conductivity, and low freezing point. Furthermore, characterization and calculations confirm that multiple types of solvation structures effectively increase the electrolyte entropy. As a consequence, the Zn/Zn symmetric cells in HEE can sustainably cycle for at least 1000 hours and 1500 hours under room and subzero temperatures, respectively. The Na0.33V2O5/Zn and polyaniline/Zn full cells can even last for 30000 and 20000 cycles without capacity decay at -20 °C, respectively. The pouch cells employing HEE deliver promising capacity and stability, even at high mass loading of active materials. This strategy of introducing multiple salts with different cations to construct a high-entropy environment provides a facile approach for high-performance and long-lifespan AZMBs across a wide temperature range.

3D-printed Bio-inspired porous electrode by bidirectional enhancement strategy with high mass loading and enhanced energy density for supercapacitors

The effective strategy for increasing areal capacity involves the use of 3D printed thick-electrode with high mass loading. However, thick-electrode still encounters challenges such as incomplete electrolyte penetration and slow ion transport. Here, we successfully prepared lignocellulosic nanofibrils (LCNFs) from abundant bamboo biomass and developed functional ink composed of LCNFs/ carbon nanotubes (CNTs) / polyaniline (PANI) / polyvinyl alcohol (PVA) for printing. An innovative 3D printing bidirectional enhancement strategy was proposed to increase the mass loading of active materials in the vertical direction and construct ion transport channels in the transverse direction. The biomimetic porous N-doped electrode obtained after annealing treatment exhibits a more continuous conductive network, larger surface area, higher utilization of active materials, and smoother ion transport pathways compared to thick-electrode. Therefore, the Triangles biomimetic electrode exhibits an enhanced areal/specific capacitance compared to thick-electrode, reaching 5.30F·cm−2 (184.03F·g−1) and 4.40F·cm−2 (122.22F·g−1) at 2 mA·cm−2, respectively. The symmetric device demonstrates an areal capacitance of 1.34F·cm−2 at 1 mA·cm−2 and achieves an energy density of 0.186 mWh·cm−2 at a power density of 0.49 mW·cm−2. The work provides valuable insights into the design of electrode structures for high-performance supercapacitors.

Hierarchical porous MnO2/3D graphene oxide/carbon cloth used as practical mass-loading supercapacitor electrodes

Supercapacitor electrodes with high mass loading of active materials often exhibit low areal capacitances due to stacking problem of heavy loading. In this study, we present a 3D hierarchical porous graphene oxide (GO) nanosheets grown on carbon cloth (CC), termed as 3DGO/CC. With its high specific surface area, ample space to accommodate the volume expansion, and ideal ion transfer pathways, 3DGO/CC emerges as a promising candidate for high-loading active materials. Utilized as an efficient support matrix for MnO2 loading, an ultrahigh mass loading of MnO2 (17.32 mg cm−2) is deposited onto the surface of 3DGO, forming a MnO2/3DGO/CC electrode without stacking. The conductive porous 3DGO/CC composite scaffold optimizes the utilization of MnO2 active material, resulting in a high areal capacitance. An optimal electrode achieves an impressive areal capacitance of 3.18 F cm−2 at 1 mA cm−2 which was 4.1 times higher than that of the pristine MnO2/CC electrode and maintains a retention of 74.5 % at 32-fold current density. Ultimately, the assembled asymmetric supercapacitor demonstrates a superior electrochemical performance with a maximum energy density of 495.36 μWh cm−2 at the power density of 1.02 mW cm−2. This study supplies an efficient method for preparing MnO2-based electrodes with excellent areal capacitance.

Sulfur-doped silicon oxycarbide by facile pyrolysis process as an outstanding stable performance lithium-ion battery anode.

Silicon oxycarbide (SiOC) is drawing significant attention as a potential anode material for lithium-ion batteries due to its remarkable cycle life and the distinctive Si-O-C hybrid bonding within its structure. However, a notable drawback of SiOC-based electrodes is their poor electrical conductivity. In this study, we synthesized sulfur-doped silicon oxycarbide (S-SiOC) via facile one-pot pyrolysis from a mixture of commercial silicone oil with 1-dodecanethiol. Upon testing the S-SiOC electrode materials, we observed significant attributes, including an outstanding specific capacity (650 mA h g-1 at 1 A g-1), exceptional capacity retention (89.2% after 2000 cycles at 1 A g-1), and substantial potential for high mass loading of active materials (up to 2.2 mg cm-2). Sulfur doping led to enhanced diffusivity of lithium ions, as investigated through cyclic voltammetry (CV) and galvanostatic intermittent titration technique (GITT) tests. Consequently, this sulfur-doped silicon oxycarbide, exhibiting excellent electrochemical performance, holds promising potential as an anode material for lithium-ion batteries.

Highly Flexible Electrodes Based on Nano/Micro‐Fiber for Flexible Lithium Metal Batteries

AbstractAlthough Li metal batteries (LMBs) with high flexibility are attractive energy storage systems for wearable devices due to their high energy density, there exist critical challenges such as limited loading density, poor dimensional stability, and thus mechanical instability under repeated mechanical deformations including bending, twisting, and folding. In this work, extremely flexible nano/microfiber composite electrodes are developed for LMBs. The highly flexible and mechanically durable electrode is composed of oxidized polyethylene terephthalate (O‐PET) microfiber (MF) substrates covered by single‐walled carbon nanotube (CNT) nanofibers (NF), prepared by mass‐producible O2 plasma treatment and spray‐coating. CNT nanofibers provided an electrical intertangled network to integrate the active materials (i.e., either NCM or passivated Li powder (PLP)) and anchored to a flexible O‐PET MF substrate, which permits high mass loading of active materials, improved electrochemical performance while maintaining mechanical durability. Resultantly, the flexible LMBs based on nano/micro fibrous electrodes have excellent energy density (300.1 Wh kg−1 electrode; nominal voltage of 3.7 V) and stable capacity retention (97.1%) without mechanical failure over 500 folding cycles.

Boosting interfacial reaction kinetics in yarn-shaped zinc-V2O5·nH2O batteries through carbon nanotube intermediate layer integration

Flexible yarn-shaped batteries are promising candidates for the wearable electronics owing to their good flexibility, tiny volume, compatibility with textiles. However, their practical applications are hindered by low capacity, active material mass loading, and energy density. Herein, we develop a coaxially wrapping strategy to fabricate an advanced yarn-shaped aqueous zinc-ion batteries (AZIBs) incorporating core-sheath carbon nanotube (CNT)/V2O5·nH2O composite yarns as cathodes and zinc wire as anodes. The as-wrapped CNT intermediate layer not only enhances the surface's conductivity, but the nano-array porous layer can also accelerate the mixing of ion concentration between the electrode surface and the electrolyte fluid through the turbulence effect, thereby improving the interfacial ion/electron kinetics. As a result, the energy storage mechanism of CNT/V2O5·nH2O yarn AZIBs transformed from capacitive-dominant to diffusion-controlled process, and the batteries demonstrate exceptional discharge capacity of 566.7 mAh g−1 at 0.1 A g−1, surpassing the state-of-art yarn-based AZIBs and approaching the theoretical zinc storage capacity (589 mAh g−1). In addition, they exhibit a high energy density of 471 Wh kg−1 at 25.5 W kg−1 and excellent cycling performance. This work opens a new and efficient avenue for the structure design of high-performance electrode materials for flexible yarn-based batteries.

Influence of Solid Fraction on Particle Size during Wet-Chemical Synthesis of β-Li3PS4 in Tetrahydrofuran

For all-solid-state batteries, the particle size distribution of the solid electrolyte is a critical factor. Small particles are preferred to obtain a high active mass loading of cathode active material and a small porosity in composite cathodes. In this work, the influence of the solid fraction in the wet-chemical synthesis of β-Li3PS4 in tetrahydrofuran (THF) is investigated. The solid fraction is varied between 50 and 200 mg/mL, and the obtained samples are evaluated using X-ray diffraction, SEM and electrochemical impedance measurements. The sizes of the resulting particles show a significant dependency on the solid fraction, while a good ionic conductivity is maintained. For the highest concentration, the particle sizes do not exceed 10 µm, but for the lowest concentration, particles up to ~73 µm can be found. The ionic conductivities at room temperature are determined to be 0.63 ± 0.01 × 10−4 S/cm and 0.78 ± 0.01 × 10−4 S/cm for the highest and lowest concentrations, respectively. These findings lead to an improvement towards the production of tailored sulfide solid electrolytes.

Development of Supercapacitors with 3D Porous Structures

AbstractThe pursuit of supercapacitors with simultaneous high power and energy densities has led to extensive research and successful outcomes through the integration of three‐dimensional (3D) electrodes, encompassing both 3D active materials and 3D porous current collectors. This mini review provides a summary of recent developments in supercapacitors featuring 3D structures. The incorporation of both 3D active materials and 3D current collectors proves effective in enhancing the mass loading of active materials without compromising their specific capacitance. The presence of pores in 3D porous current collectors contributes to additional double‐layer capacitance by offering a large surface area. Moreover, 3D porous transition metal current collectors can provide both double‐layer and faradic capacitances through the in‐situ surface oxidation mechanism. Beyond materials and geometries, this review also discusses synthesis strategies for electrodes, offering insights into the process‐structure‐property relationship crucial for supercapacitors. By combining 3D active materials with 3D current collectors, the energy density of supercapacitors could be substantially improved.

Practical organic batteries: Concepts to realize high mass loading with high performance.

Organic electrode materials (OEMs) have been well developed in recent years. However, the practical applications of OEMs have not been paid sufficient attention. The concept here focused on one of the essential aspects for practical applications, i. e., high mass loading of active materials. This paper summarizes the challenges posed by high-mass loading of active materials in organic batteries and discusses the possible solutions in terms of organic electrode materials, conductive additives, electrode structures, and electrolytes or battery systems. We hope this concept can stimulate more attention to practical applications of organic batteries towards industry from lab.

Highly Efficient Aligned Ion-Conducting Network and Interface Chemistries for Depolarized All-Solid-State Lithium Metal Batteries

HighlightsThis study introduces an innovative 3D-printed electrolyte with vertically aligned ion transport network, which contains well-dispersed nanoscale Ta-doped Li7La3Zr2O12 in a poly(ethylene glycol) diacrylate matrix.The 3DSE architecture enables efficient ion transport across the Li/electrolyte and electrolyte/cathode interfaces, which allows for increased active material mass loading and enhanced interfacial adhesion.The p-3DSE Li symmetric cell displays an impressive critical current density value of 1.92 mA cm−2 and stable operation for 2600 h at room temperature. Full cells using p-3DSE achieve notable areal capacities.

New approaches to three-dimensional positive electrodes enabling scalable high areal capacity

A novel in situ powder infiltration method was used to fabricate 3D positive electrodes with scalable high areal capacity, highlighting the high mass loading of active materials and interfaces of binder-free 3D electrodes.

Monolithic porous carbon membrane-based hybrid electrodes with ultrahigh mass loading carbon-encapsulated Co nanoparticles for high-performance supercapacitors

Monolithic carbon membrane-based hybrid electrodes with an ultrahigh active mass loading are developed by carbonization of Co-adsorbed Pleurotus eryngii (PE) for directly assembling a supercapacitor with high energy density and cycling stability.

Synchronously promoting the electron and ion transport in high-loading Mn2.5V10O24∙5.9H2O cathodes for practical aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are suitable candidates for stationary energy storage systems because of their inherent safety and affordability. However, the development of high-performance and high-loading ZIB cathode facing actual requirements is still a great challenge. Herein, we report Mn2.5V10O24∙5.9H2O (MVOH) as a high-loading cathode for aqueous ZIB. Combined experimental data and material simulations reveal that the inserted Mn2+ ions can regulate the electronic structure and defective state of the MVOH cathode, leading to high electric conductivity, reduced Zn2+ ion diffusion barrier, and good structural stability. Benefited from the synergistically enhanced electron and Zn2+ ion transport properties, the high-loading (11.7 mg cm−2) MVOH cathode obtains a high areal specific capacity of 3.74 mAh cm−2 and an outstanding capacity retaining rate of 91.4 % for 850 cycles at 0.5 A g−1. Noteworthy, a maximum areal capacity of 7.2 mAh cm−2 is reached at the active material mass loading of as high as 19.9 mg cm−2, exceeding most of the literature-reported results. The reversible Zn2+ ion storage behavior is also demonstrated by various ex-situ characterizations and pouch-type full cell evaluations. This work might deepen the Zn2+ ion storage knowledge of the high-loading vanadium-based cathodes and further promote the practical competitiveness of aqueous ZIBs.

Fabrication of a 3D structure MnO2 electrode with high MnO2 mass loading as the cathode for high-performance aqueous zinc-ion batteries

Benefiting from the remarkable advantages (eco-friendly, cost-effective, and high safety) of rechargeable aqueous zinc-ion batteries (AZIBs), AZIBs are regarded as viable alternatives to traditional Lithium-ion batteries (LIBs). However, in prevailing research, the excellent electrochemical performance usually achieved by ultra-low active material loadings (e.g., <1 mg/cm²), which is far from the active material mass loading of commercial electrodes in practical (≥10 mg/cm²). Balancing superior properties with high mass loading has posed a challenge. To surmount this, an innovative method combined ultrasonic processing, freeze-drying, and 3D printing technologies is used to engineer a high MnO2 mass loading cathode for AZIBs (3D cathode). Notably, the grid structure of 3D cathode substantially augmenting the surface area for redox reactions during charge/discharge processes, which greatly enhanced the pseudo-capacitance process of cathode. Additionally, the uniform and stable microstructure exhibited the dual capability of expediting ion/electron transfer and sustaining the structural integrity throughout charge/discharge cycles. Consequently, the 3D cathode demonstrated superior comprehensive electrochemical properties at the MnO2 high mass loading of 10 mg/cm2 (138.7 mAh/g at 1 A/g, 87.4 mAh/g after 500 cycles, 82 % energy efficiency) and 15 mg/cm2 (113.3 mAh/g at 1 A/g, 56.3 mAh/g after 400 cycles, 81 % energy efficiency).

High performance supercapacitors based on WS2 nanoflower electrodes with commercial-level mass-loading

Supercapacitors with a commercial-level mass loading of active materials are designed to offer greater energy storage capacity than conventional supercapacitors. For the first time, we are reporting the fabrication and performance studies of a symmetric supercapacitor with 30 mg cm−2 commercial-level mass loading of 2D WS2 nanoflower electrode material, which exhibited superior electrochemical performance. At 5 mV s–1 specific capacitance achieved by the device is 204 F g–1. At 1 A g–1, the supercapacitor provides impressive specific energy and power values of 14 Wh kg−1 and 0.8 kW kg−1, respectively. The device maintains an exceptional cycling stability of 100 % over 10,000 cycles of continuous charging and discharging. Furthermore, supercapacitor coin cells fabricated using commercial-level-mass loaded 2D WS2 electrodes are used to power an LED.

Electrophoretic Deposition of Poly(ethylene oxide) Gel-Polymer Electrolyte for 3D NiO/Ni Foam Anode Based Lithium-Ion Batteries

The goal to further increase energy and power density of conventional 2D structured lithium-ion batteries is driving research towards more complex 3D batteries with large surface area and accordingly high active material mass loading. So far, many attempts have been implemented to prepare 3D structured LIBs. However, the hindrance of the realization comes with removing the separator which requires conformally and homogeneously coating the scaffolded areas of the electrode. The conformal coating of polymer electrolyte without any defects on the surface of the electrode is one of the most essential and challenging problems to solve to avoid the short circuit between the anode and cathode compartments of the 3D LIBs. In this paper, electrophoretic deposition technique was successfully used for the first time to coat the 3D NiO on the nickel foam anode with polyethylene oxide (PEO) gel-polymer electrolyte. The resulting polymer electrolyte was thin and uniform with the thickness range of 2.5–3.0 μm. The developed NiO@Ni foam anode coated by PEO gel-polymer electrolyte exhibited outstanding cycling stability of 100 cycles at 0.1 C rate, delivering a capacity of 406 mAh g−1. This simple coating approach allowed a cell operation at room temperature without a commercial separator, which is an excellent result for further developing high-energy-density 3D batteries.

Assessing n‐type organic materials for lithium batteries: A techno‐economic review

AbstractThe high demand for critical minerals such as lithium, copper, nickel, and cobalt, required for lithium‐ion batteries, has raised questions regarding the feasibility of maintaining a steady and affordable supply of raw materials for their production. In the last years, researchers have shifted their attention toward organic materials, which are potentially more widely available, affordable, and sustainable due to the ubiquitous presence of the constituent organic elements. The n‐type materials have a redox mechanism analogous to that of lithium‐ion cathodes and anodes, hence they are suitable for a meaningful comparison with the state‐of‐the‐art technology. While many reviews have evaluated the properties of organic materials at the material or electrode level, herein, the properties of n‐type organic materials are assessed in a complex system, such as a full battery, to evaluate the feasibility and performance of these materials in commercial‐scale battery systems. The most relevant cathode materials for organic batteries are reviewed, and a detailed cost and performance analysis of n‐type material‐based battery packs using the BatPaC 5.0 software is presented. The analysis considers the influence of electrode design choices, such as the conductive carbon content, active material mass loading, and electrode density, on energy density and cost. The potential of n‐type organic materials as a low‐cost and sustainable solution for energy storage applications is highlighted, while emphasizing the need for further advancements of organic materials for energy storage applications.image

Cellulose degradation of cottonseed meal derived porous carbon for supercapacitor

Enzyme, as a type of biocatalyst, has a superior degradability on the biomass component. Herein, the cellulase degradation of cottonseed meal (CCM) is used as carbon source and potassium citrate as activating agent to fabricate O, S, N co-doped carbon materials. Cellulase pretreatment degrades the cellulose (from 12.48 wt% to 2.24 wt%) of cottonseed meal (CM) as well as creates the pore structure. Most importantly, the enzymolytic process can enhance the O content and improve the activation efficiency of potassium citrate. The optimized CCM-800-2 with hierarchical porous structure and high O (11.33 at%) content exhibits a high specific capacitance of 364 F g-1 in 6 M KOH electrolyte. In addition, the assembled potassium citrate-chitosan gel electrolyte-based symmetric supercapacitor with 20 mg cm-2 mass loading of active material shows a high energy density of 28.8 Wh kg-1. This study provides an efficient enzyme assisted pretreatment and low activator ratio strategy to prepare biomass-based porous carbon, and expects to fabricate more carbon materials using other carbon precursors.

High Energy Density Porous RuO2 micro-Supercapacitors Using Protic Ionic Liquid Electrolytes

The rapid development of the Internet of Things (IoT) demands reliable and long-term energy supply to microelectronic devices distributed over the network with high power performance and less maintenance required.[1] Micro-supercapacitors (MSCs) have come to the foreground as miniaturized energy storage devices showing outstanding power density and long cycle life. However, the low cell voltage and low energy density remain major bottleneck that prevents their adoption in real device applications. To this end, several studies have been devoted to the engineering of MSC electrode materials and structural architecting of current collectors within the limited available footprint. This approach could offer opportunities to enhance the electrochemically active surface and mass loading of active materials with fast ion diffusion kinetics, leading to high areal energy density performance.[2] Although several efforts have been put forth in this direction, the complex synthesis route, unfavourable interfacial and mechanical stability of the electrode, electrolyte compatibility issues, etc. remain an arduous challenge.[3] The low cell voltage is another major issue preventing from achieving high energy density values in MSCs as it is directly linked to the electrochemical stability window (ESW) of the electrolytes used.[4] In addition, liquid-state electrolytes currently employed are inappropriate for the microfabrication route as it is prone to evaporation, leakage, and potential safety issues. Hence, a lot of research attention has been given to developing solid-state electrolytes able to afford large operational windows and help promote the application of on-chip MSCs. In this work, we have demonstrated the use of protic ionic liquid (PIL)-based electrolytes able to provide pseudocapacitance in hydrous ruthenium dioxide (RuO2) electrodeposited on interdigitated MSC substrates with extended operational cell voltage. As a pseudocapacitive material, RuO2 exhibits excellent conductivity, high electrochemical reversibility, and cycling stability.[5] On the other hand, as room temperature molten salts, PILs help to overcome evaporation and encapsulation problems associated with the conventional aqueous electrolytes and flammability and safety issues linked to common organic electrolytes.[6-9] We explored pyrrolidinium-based PILs with varying alkyl substitutions, their structure-property, and electrochemical studies for RuO2 MSCs. To further expand the use of these PILs in real devices, 3D MSCs with higher active material mass loading was realised using interdigitated porous Au current collector substrates. The PIL-based porous RuO2 MSCs showed superior charge storage and higher energy density performance as compared to conventional aqueous electrolytes. To envision the practical application of RuO2 MSCs and their subsequent integration with microelectronic devices, ionogel-based solid-state electrolytes were developed. This work opens pathways to develop micro-supercapacitors exhibiting high energy and power density by combining pseudocapacitive metal oxide-based active materials and protic ionic-liquid-based non-aqueous electrolytes and help their integration with on-chip IoT devices.