Remarkable Capacity Retention Research Articles

Chemical and physical synergism between PAF-54 and SFPEEKK for effective shuttle effect inhibition of lithium–sulfur battery

Lithium-sulfur batteries (LSBs) have garnered considerable interest due to their high theoretical discharge specific capacity and energy density. However, the formation of lithium polysulfides during the electrochemical redox process leads to the loss of active material and undesirable electrochemical properties. In this study, we developed a novel Janus separator (FSP-PAF) prepared by coating PAF-54 compounded sulfonated poly (ether ether ketone ketone) and Super P onto the PE separator to effectively mitigate the shuttle effects. The FSP-PAF exhibited a high ionic conductivity of 6.4 × 10−4 S/cm and a Li+ transfer number (tLi+) of 0.72. Lithium-sulfur batteries assembled with FSP-PAF demonstrated a capacity of 1112 mA h/g at 0.2 °C, and a remarkable capacity retention rate of 65 % after 500 cycles, and maintained a capacity of 720 mA h/g even at a high rate of 3 °C. This synergistic effect involving PAF-54, sulfonated poly (ether ether ketone ketone), and Super P held great promise for the application of LSBs.

In-situ thermal reduction synthesis of porous carbon nitride doped gadolinium sulfide nanocomposite: An emerging electrode material for high-performance supercapacitor

The multiple-step synthesis, harmful organic solvents, and hazardous binders are the major obstacles for supercapacitor (SC) designers. A conventional synthesis of nanocomposite is normally involves complex steps and time-consuming. To reduce these multiple steps and process time, we report carbon nitride-doped gadolinium sulfide (CN/Gd2S3) nanocomposite obtained via a one-step in situ thermal reduction method. In our study, we introduce poly(3,4-ethylenedioxythiophenes): polystyrene sulfonate (PEDOT–PSS) to act as a dual role of binder and conducting additive, and we use DI water as the solvent for the SC electrode. Despite the reduced fabrication steps, our electrode exhibits an extraordinary specific capacity valueof 1831 F g−1 at 1 A g−1 in an aqueous 2 M KOH electrolyte, as well as 98.5 % retention after 5000 cycles. Moreover, a solid-state asymmetric SC (ASC) was further made up with activated carbon (AC) as a negative electrode and CN/Gd2S3 as a positive electrode, providing a high energy density of 70.95 W h kg−1 at a specific power density of 250 W kg−1 at 1 A g−1. The remarkable specific capacitance retention of the ASC could maintain 86.8 % after 5000 cycles, indicating the potential application of CN/Gd2S3 electrode material for energy storage devices. This device (CN/Gd2S3//AC) showcased its practical application by powering twenty-six light-emitting diodes (LEDs) (each of 2.7 V) and appeared as an attractive energy storage unit for portable devices.

Design and synthesis of bifunctional conjugated microporous polymers containing tetraphenylethene and bisulfone units for energy storage and fluorescent sensing of p-nitrophenol

In this study, we successfully used the Suzuki-Miyaura reaction to prepare three novel conjugated microporous polymers (CMPs) that include tetraphenylethene (TPE): TPE-Ph-Th, TPE-Ph-Tha, and TPE-Ph-BSu. Using methods like FTIR and solid-state NMR, we examined the chemical composition and functional groups in the TPE-Ph CMPs. The TPE-Ph-BSu CMP's thermal characteristics were also examined, and they showed remarkable features with a decomposition temperature (Td10) of 535 °C and a char yield of 73 wt%. We also looked at TPE-Ph-Th CMP, which had a pore size of 2.0 nm and a surface area (SBET) of 67 m2 g−1. We carried out photoluminescence (PL) and electrochemical investigations to evaluate the potential of TPE-Ph CMPs for supercapacitor applications and their capability to detect p-nitrophenol (PNP). According to our electrochemical investigation, the TPE-Ph-Tha and TPE-Ph-BSu CMPs both exhibited exceptional capacitance, reaching 51 and 52 F g−1 at a current density of 0.5 A g−1, respectively. Furthermore, even after 5000 cycles, these CMPs still retained 80% of their capacitance, demonstrating their remarkable capacitance retention. In conclusion, synthetic TPE-Ph CMPs have several benefits, including outstanding electrochemical performance and thermal stability. Additionally, they successfully detect PNP using fluorescence-based sensing without interference, making them adaptable materials suited for a variety of applications, including the detection of pollutants (as PNP has shown) and the usage of supercapacitors.

High-performance energy storage hybrid supercapacitor device based on NiCoS@CNT@graphene composite electrode material

The novel asymmetric supercapacitor, sometimes referred to as a ‘supercapattery,’ merges the favourable attributes of batteries, such as high energy density, with the exceptional cycle life and specific power of supercapacitors (SCs). In this study, carbon nanotubes and graphene were physically mixed with nickel cobalt sulfide (NiCoS), which was produced using a hydrothermal method. Using both a three-electrode and a two-electrode arrangement, the material’s electrical properties were carefully examined. The NiCoS@CNT@graphene composite exhibited a striking specific capacity (Qs) of 1814 C g−1 at 2 Ag−1, within the three-electrode system. The NiCoS@CNT@graphene//AC composite hybrid device revealed outstanding Qs of 190 Cg−1 at 2 Ag−1. Additionally, this material demonstrated an exceptional power density (Pd) of 2000 W kg−1 and a noteworthy Ed of 40.5 Wh Kg−1. The nanocomposite electrode showed remarkable capacity retention (CR ∼ 88%) after 5000 cycles, which was one of its most notable features, highlighting its long-term stability and potential for extensive usage. A viable strategy includes mixing transition metal sulfides with conductive carbon-based nanomaterials to produce high-performance energy storage devices with surpassed capabilities.

Adaptive Multi‐Site Gradient Adsorption of Siloxane‐Based Protective Layers Enable High Performance Lithium‐Metal Batteries

AbstractLow Coulombic efficiency and significant capacity decay resulting from an unstable solid electrolyte interphase (SEI) and dendritic growth pose challenges to the practical application of lithium‐metal batteries. In this study, a highly efficient protection layer induced by octaphenylsilsesquioxane (OPS) with LiFSI salt is investigated. The OPS exhibits a strong adsorption energy with lithium, its multi‐site gradient adsorption ability enables the simultaneous capture of 8 Li+ and the uniform regulation of Li ion flux. Moreover, the mechanical strength and electronic insulation of the OPS layer induces Li deposition under the protection layer and effectively inhibits lithium dendrite growth. Such a protection layer contributes to the stable and dendrite‐free performance of a lithium‐metal battery employing LiNi0.8Co0.1Mn0.1O2 (NCM811) as a cathode and an ultrathin OPS‐protected lithium foil (20 µm) as the anode. A remarkable capacity retention of 91.4% is achieved after 300 cycles at 1C. The OPS‐protected Li anodes and NCM811 are also tested in combination with a Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte, showing extended cyclability up to 300 cycles with an average Coulombic efficiency of 99.58% and capacity retention of 85.7%.

Anhydride-Based Compound with Tunable Redox Properties as Advanced Organic Cathodes for High-Performance Aqueous Zinc-Ion Batteries.

Organic materials with multiple active sites and flexible structural designs are becoming popular for use in aqueous zinc-ion batteries (AZIBs). However, their applicability is limited due to the low specific capacity and poor cycle stability originating from the introduction of inactive units and high solubility. Herein, three organic molecules with tunable redox properties were synthesized using anhydride (PMDA, 1,2,4,5-benzenetetracarboxylic anhydride-1,2-diaminoanthraquinone, NTCDA, 1,4,5,8-naphthalenetetracarboxylic dianhydride-1,2-diaminoanthraquinone, and PTCDA, 3,4,9,10-perylenetetracarboxylic dianhydride-1,2-diaminoanthraquinone, referred to as PM12, NT12, and PT12) in the solid-phase method. Density functional theory (DFT) simulations and experiments identified that NT12 exhibits superior electrochemical performance compared with PM12 and PT12 because of the low energy gap and large aromatic conjugated structure. They demonstrated specific capacities of 106.7, 192.9, and 124.9 mA h g-1 at 0.05 A g-1, respectively. Especially, NT12 displayed excellent initial specific capacity (85.4 mA h g-1 at 1 A g-1) and remarkable capacity retention (64.1% for 3000 cycles) due to dual active centers (C═N and C═O). The all-NT12 full-cell also had excellent performance (127.1 mA h g-1 under 1 A g-1 and 80.6% over 200 cycles). The organic compounds synthesized in this work have potential applications of AZIBs, highlighting the importance of molecular design to develop the next generation of advanced materials.

Regulating Anionic Redox via Mg Substitution in Mn-Rich Layered Oxide Cathodes Enabling High Electrochemical Stability for Sodium-Ion Batteries.

With the limited resources and high cost of lithium-ion batteries (LIBs) and the ever-increasing market demands, sodium-ion batteries (SIBs) gain much interest due to their economical sustainability, and similar chemistry and manufacturing processes to LIBs. As cathodes play a vital role in determining the energy density of SIBs, Mn-based layered oxides are promising cathodes due to their low cost, environmental friendliness, and high theoretical capacity. However, the main challenge is structural instability upon cycling at high voltage. Herein, Mg is introduced into the P2-type Na0.62 Ni0.25 Mn0.75 O2 cathode to enhance electrochemical stability. By combining electrochemical testing and material characterizations, it is found that substituting 10 mol% Mg can effectively alleviate the P2-O2 phase transition, Jahn-Teller distortion, and irreversible oxygen redox. Moreover, structural integrity is greatly improved. These lead to enhanced electrochemical performances. With the optimized sample, a remarkable capacity retention of 92% in the half cell after 100 cycles and 95% in the full cell after 170 cycles can be achieved. Altogether, this work provides an alternative way to stabilize P2-type Mn-based layer oxide cathodes, which in turn, put forward the development of this material for the next-generation SIBs.

Cellulose graphitic carbon directed iron oxide interfaced polypyrrole electrode materials for high performance supercapacitors

The rising demand for green and clean energy urges the enlargement of economical and proficient electrode materials for supercapacitors. Herein, we designed a novel electrode material by porous cellulose graphitic carbon (CC) derived from bio-waste cornhusk via the pyrolysis route, and α-Fe2O3 decorated nanostructure with CC (CCIO) was achieved in situ pyrolysis of corn-husk and Fe(NO3)3·9H2O metal salt followed by a coating of polypyrrole (CCIOP). The CC, CCIO, and CCIOP nanocomposite electrodes were characterized by XRD, Raman, FTIR, FE-SEM/EDX, FE-TEM, XPS, and BET analysis. The CCIOP nanocomposite electrode exhibits an enhanced specific capacitance (Csp) of 290.9 F/g, which is substantial to its pristine CC (128.3 F/g), PPy (140.3 F/g), and CCIO (190.7 F/g). The Csp of CCIOP in a three-electrode system, using 1 M Na2SO4 electrolyte exhibits excellent capacity retention of 79.1 % even at a high current density of 10 A/g. The as-fabricated asymmetric supercapacitor (ASC) delivered a remarkable capacity retention of 88.7 % with a coulombic efficiency of 98.8 % even after 3000 cycles. The study shows successful utilization of cellulose from bio-waste cornhusk into a substantial template applicable in future alternative energy storage devices.

Synthesis of CNTs Doped Nickel Copper-Sulfides Composite Electrode Material for High-Performance Battery-Supercapacitor Hybrid Device

The hybrid supercapacitor combines the outstanding energy density characteristics of batteries with the remarkable durability and unique power characteristics of supercapacitors (SCs). Herein, a hydrothermal technique was applied to produce nickel-copper sulfide (NiCuS), which was later physically embedded into carbon nanotubes. In this study, a three and two electrode measurement systems were studied. To confirm the battery type nature of the electrode materials, a three-electrode assembly was used. For hybrid device, a two-electrode measurement scheme was employed. In the three-electrode setup, the NiCuS@CNT composite revealed a superior specific capacity (Qs) of 1110.0 C g−1. The NiCuS@CNT//AC nanocomposite based hybrid device established a remarkable Qs of 620.9 C g−1. Additionally, the NiCuS@CNT//AC exhibited a remarkable energy density (Ed) of 29.5 Wh kg−1 and a power density (Pd) of 2165.0 W kg−1.This composite material is distinguished for its remarkable capacity retention, maintaining an amazing 88.2% of its capacity after 8000 cycles. This emphasizes its continued stability and the possibility of having a longer operating lifespan. By advancing energy storage technologies, this dynamic integration might provide brand-new, exciting opportunities.

Scalable Preparation of Polyimide Sandwiched Separator for Durable High-Rate Lithium-Metal Battery.

The ever-growing demands for efficient energy storage accelerate the development of high-rate lithium-metal battery (LMB) with desirable energy density, power density, and cycling stability. Nevertheless, the practical application of LMB is critically impeded by internal temperature rise and lithium dendrite growth, especially at high charge/discharge rates. It is highly desired but remains challenging to develop high-performance thermotolerant separators that can provide favorable channels to enable fast Li+ transport for high-rate operation and simultaneously homogenize the lithium deposition for dendrite inhibition. Polyimide-based separators with superior thermal properties are promising candidate alternatives to the commercial polyolefin-based separators, but previous strategies of designing either nanoporous or microporous channels in polyimide-based separators often meet a dilemma. Here, a facile and scalable approach is reported to develop a polyimide fiber/aerogel (denoted as PIFA) separator with the microporous polyimide fiber membrane sandwiched between two nanoporous polyimide aerogel layers, which can enable LMBs with remarkable capacity retention of 97.2% after 1500 cycles at 10 C. The experimental and theoretical studies unravel that the sandwiched structure of PIFA can appreciably enhance the electrolyte adsorption and ionic conductivity; while, the aerogel coating can effectively inhibit dendrite growth to realize durable high-rate LMBs.

Printed flexible supercapacitor from conductive ink of graphite nanocomposite blended with Co3O4 to facilitate the fabrication of energy storage device

An easy-to-make and potential technique for designing of supercapacitor has been proposed by printing conductive ink from porous Co3O4 and graphite nanocomposite. This method simplifies the process of fabrication of energy storage devices. The ink used in this fabrication was prepared after blending the porous Co3O4 nanoparticle composite with graphite, porous Co3O4 nanosphere was synthesized in situ through a single-step calcination process of the zeolitic imidazolate framework precursor (ZIF-67). To ensure homogenous fabrication, the supercapacitor was prepared by screen-printing technology, which allowed for the even distribution of ink using a standard squeeze spreader. The performance was evaluated by designing two types of supercapacitors: an ultra-flexible symmetric supercapacitor (CG-1) and an asymmetric supercapacitor (ASSC), both of which utilized the solid polymeric electrolyte with a resistance of 4.92 Ω. Our research showed an enhanced specific capacitance of 85 Fg−1 for CG-1 and 137 Fg−1 for ASSC, indicating the high efficiency of these lab-created screen-printed supercapacitor devices. The ASSC supercapacitor exhibited remarkable capacitance retention (%). After 2500 cycles, it retained 96.3 %, and even after 5000 cycles, it retained 85.9 %. The results highlight its exceptional flexibility and durability, with a retention rate ranging from 97.8 % to 99.3 % when subjected to various bending angles. Finally, the current works present the fabrication of supercapacitors using a user-friendly screen-printing technique, where ink was prepared by the optimal recipe of ZIFs and graphite nanocomposite. Our approach involved preparing an ink with an optimized recipe of zeolitic imidazolate frameworks (ZIFs) and graphite nanocomposites. It emphasizes the promising prospects of employing metal-organic frameworks, specifically ZIFs, as effective templates for producing porous electrode materials. This breakthrough paves the way for the production of innovative devices and their application in the future of state-of-the-art flexible energy storage.

Sodium Layered/Tunnel Intergrowth Oxide Cathodes: Formation Process, Interlocking Chemistry, and Electrochemical Performance.

Manganese-based layered oxides are prospective cathode materials for sodium-ion batteries (SIBs) due to their low cost and high theoretical capacities. The biphasic intergrowth structure of layered cathode materials is essential for improving the sodium storage performance, which is attributed to the synergistic effect between the two phases. However, the in-depth formation mechanism of biphasic intergrowth materials remains unclear. Herein, the layered/tunnel intergrowth Na0.6MnO2 (LT-NaMO) as a model material was successfully prepared, and their formation processes and electrochemical performance were systematically investigated. In situ high-temperature X-ray diffraction displays the detailed evolution process and excellent thermal stability of the layered/tunnel intergrowth structure. Furthermore, severe structural strain and large lattice volume changes are significantly mitigated by the interlocking effect between the phase interfaces, which further enhances the structural stability of the cathode materials during the charging/discharging process. Consequently, the LT-NaMO cathode displays fast Na+ transport kinetics with a remarkable capacity retention of ∼70.5% over 300 cycles at 5C, and its assembled full cell with hard carbon also exhibits high energy density. These findings highlight the superior electrochemical performance of intergrowth materials due to interlocking effects between layered and tunnel structures and also provide unique insights into the construction of intergrowth cathode materials for SIBs.

Enhancing pseudo-capacitive behavior in Mn-doped Co3O4 nanostructures for supercapacitor applications

The study focused on Mn-doped Co3O4 samples, which were synthesized successfully using the coprecipitation method and subsequently annealed at 600 °C. The X-ray diffraction (XRD) patterns displayed distinct peaks corresponding to the spinel-cubic structure of Co3O4. Notably, these patterns indicated a preference for (311) plane orientations, which shifted toward lower diffraction angles as the concentration of Mn increased. The analysis of crystallite sizes for the Mn-doped Co3O4 nanoparticles revealed values of 40 nm, 38 nm, and 38 nm for Co3O4:3%Mn, Co3O4:5%Mn, and Co3O4:7%Mn, respectively. Employing X-ray photoelectron spectroscopy (XPS), the study provided insights into the chemical constituents and valence states of the samples. It revealed the presence of both Co2+ and Co3+ ions, along with different oxygen states. The investigation into the electrochemical behavior of the Mn-doped Co3O4 nanostructures highlighted their pseudo-capacitive nature. The specific capacitance and cyclic stability of these structures were found to be contingent on the concentration of Mn doping. Electrochemical impedance spectroscopy (EIS) data unveiled low interfacial charge resistance and enhanced ion diffusion rates. Notably, the most striking results were observed with the 7 wt% Mn-doped Co3O4 nanomaterials. These materials exhibited an outstanding specific capacitance of 537 F/g at a current density of 1.5 A/g. Additionally, they demonstrated remarkable capacity retention of 94% over a span of 1500 cycles. In conclusion, the Mn-doped Co3O4 nanostructures showcased promising electrochemical performance, which could render them suitable for potential applications in supercapacitors.

Accelerating Sulfur Redox Chemistry by Atomically Dispersed Zn-N4 Sites Coupled with Pyridine-N Defects on Porous Carbon Sheets.

Single-atom catalysts (SACs) with specific N-coordinated configurations immobilized on the carbon substrates have recently been verified to effectively alleviate the shuttle effect of lithium polysulfides (LiPSs) in lithium-sulfur (Li─S) batteries. Herein, a versatile molten salt (KCl/ZnCl2 )-mediated pyrolysis strategy is demonstrated to fabricate Zn SACs composed of well-defined Zn-N4 sites embedded into porous carbon sheets with rich pyridine-N defects (Zn─N/CS). The electrochemical kinetic analysis and theoretical calculations reveal the critical roles of Zn-N4 active sites and surrounding pyridine-N defects in enhancing adsorption toward LiPS intermediates and catalyzing their liquid-solid conversion. It is confirmed by reducing the overpotential of the rate-determining step of Li2 S2 to Li2 S and the energy barrier for Li2 S decomposition, thus the Zn─N/CS guarantees fast redox kinetics between LiPSs and Li2 S products. As a proof of concept demonstration, the assembled Li─S batteries with the Zn─N/CS-based sulfur cathode deliver a high specific capacity of 1132mAhg-1 at 0.1C and remarkable capacity retention of 72.2% over 800cycles at 2C. Furthermore, a considerable areal capacity of 6.14mAhcm-2 at 0.2C can still be released with a high sulfur loading of 7.0mgcm-2 , highlighting the practical applications of the as-obtained Zn─N/CS cathode in Li─S batteries.

Carbon-Coated Sodium Vanadium Phosphate Nanocomposites as Efficient Cathode Materials for Sodium-Ion Batteries and Capacitors

Sodium vanadium phosphate (Na3V2(PO4)3) with continuous carbon-coating (NVP/C) has been regarded as one of the most promising cathode materials for sodium-ion batteries (SIBs) owing to the three-dimensional sodium superionic conductor (NASICON) structure for fast sodium-ion migrations, high theoretical energy density (ca. 400 Wh/ kg), and good thermal stability (450°C). In this study, NVP/C nanoparticles (NPs) were successfully synthesized by employing ascorbic acid as the reductant and carbon source simultaneously, followed by calcination at 750°C in an argon atmosphere. The NVP/C NPs possessed great crystallinity, high purity, size of 100-200 nm, coated carbon layer of 5-10 nm, and carbon amounts of 8.5 wt. % were confirmed through the X-ray diffractometer, transmission electron microscope, and thermogravimetric analyzer, respectively. The remarkable reversible capacity (75 mAh/g at 0.1 C), rate capability (62 mAh/g at 2 C), and capacity retention (~100% after 1,000 cycles at 1 C) were delivered from the NVP/C half-cell. Encouraged by these impressive results, the asymmetric sodium-ion capacitors (SICs) consisted of the NVP/C cathode, free-standing hydrogel-derived hierarchical porous activated carbon (H-HPAC) anode, and organic electrolyte were also assembled to explore the electrochemical performances. As revealed, excellent rate capabilities were also achieved, i.e., 44 mAh/g at 0.45 A/gNVP and 28 mAh/g at 4.5 A/gNVP. Accordingly, the NVP/C NPs synthesized in the present study are reasonably believed to serve as potential cathode materials for SIBs and SICs. Figure 1

Topology Optimization of Prelithiated Sio for Improving Dimensional Stability

As the demand for high energy density materials of lithium ion batteries increases, silicon monoxide is considered one of the promising anode materials that can replace the conventional anode materials. However, the low initial Coulombic efficiency(ICE) and the poor cycle stability bottlenecks the commercialization of SiO material. Although numerous efforts have been made, these two chronic issues of SiO have not been solved simultaneously. Here, we demonstrated a prelithiation method to improve the ICE as well as cycle ability by optimizing the topology of prelithiated SiO. Calorimetric method and LA-APT analysis revealed that four exothermic reactions are related with the topology and microstructure of prelithiated SiO. At the optimum heat treatment temperature of 650 ℃, the prelithiated SiO showed a capacity of 1164 mAh g-1 with an ICE of 89.6 % and a remarkable capacity retention of 73.4 % at 300 cycles. We also found that the optimized electrode expanded less compared to non-optimized prelithiated SiO materials. The outstanding electrochemical properties were attributed to the modulated topological arrangement of the active Si phase and Li2SiO3 inactive buffer phase. Further description of the topological optimization will be discussed in the presentation.

In Situ N, O-Dually Doped Nanoporous Biochar Derived from Waste Eutrophic Spirulina for High-Performance Supercapacitors.

Sustainable and high-performance energy storage materials are crucial to address global energy and environmental challenges. In this study, Spirulina platensis was used as the carbon and nitrogen source, and Spirulina-based nanoporous biochar (SNPB) was synthesized through chemical activation using KOH as the activating agent in N2 atmosphere. SNPB-800-4 was characterized by N2 adsorption-desorption and XPS, showing a high specific surface area (2923.7 m2 g-1) and abundant heteroatomic oxygen (13.78%) and nitrogen (2.55%). SNPB-800-4 demonstrated an exceptional capacitance of 348 F g-1 at a current density of 1 A g-1 and a remarkable capacitance retention of 94.14% after 10,000 cycles at a current density of 10 A g-1 in 6 M KOH. Notably, symmetric supercapacitors SNPB-800-4//SNPB-800-4 achieved the maximum energy and power densities of 17.99 Wh kg-1 and 162.48 W kg-1, respectively, at a current density of 0.5 A g-1, and still maintained 2.66 Wh kg-1 when the power density was increased to 9685.08 W kg-1 at a current density of 30 A g-1. This work provides an easily scalable and straightforward way to convert waste algae biomass into in situ N, O-dually doped biochar for ultra-high-power supercapacitors.

Electrochemically Finely Regulated NiCo‐LDH/NiCoOOH Nanostructured Films for Supercapacitors with Record High Mass Loading, Areal Capacity, and Energy Density

AbstractThe design of supercapacitor materials with both high mass loading and high areal capacity is a major strategy to overcome relatively low energy density of supercapacitors. Herein, NiCo‐layered double hydroxide (NiCo‐LDH)/NiCoOOH composite films with both ultrahigh mass loading and high areal capacity are prepared by a two‐step cyclic voltammetry method. The films consist of NiCo‐LDH/NiCoOOH microspheres assembled with ultrafine nanosheets with highly ordered pore distribution from macropores to micropores and abundant defect active sites, which are conducive to the transport of electrolyte ions, increasing the reaction kinetics, and greatly improving the utilization of active material. The optimal film with hierarchical microstructure featuring an ultrahigh mass loading of 80 mg cm−2 not only exhibits a state‐of‐the‐art high areal capacity of 14.7 mAh cm−2, but also shows a record‐high energy density of 10.7 mWh cm−2 , as well as presents remarkable mechanical stabilityand superior capacity retention of 99% after 20000 galvanostatic charge‐discharge cycles. Moreover, by combining the experimental analysis and theoretical calculations, the mechanism of preferential conversion of the NiCo‐LDH in the subtle defect region to NiCoOOH by electrochemistry and the synergistic effect in electrochemical energy storage of the NiCo‐LDH and NiCoOOH phases is proposed.

Enabling Structure/Interface Regulation for High Performance Ni‐Rich Cathodes

AbstractFurther commercialization of Ni‐rich layered cathodes is hindered by severe structure/interface degradation and kinetic hindrance that occur during electrochemical operation, which leads to safety risks and reduced range in electric vehicles (EVs). Herein, by selecting elements with different solubility properties, a multifunctional strategy that synchronously fabricates perovskite‐type SrZrO3 coating and Sr/Zr co‐doping is employed to strengthen the structure/interface stability and the Li+ transport mobility of LiNi0.85Co0.10Mn0.05O2 (NCM). Perovskite‐type SrZrO3 protective layers formed on the particle surface can substantially mitigate the unexpected interfacial side reactions and surface phase transitions. In addition, a robust crystal framework is constructed by optimizing local O coordination through the introduction of strong Zr−O bonds. Notably, Li+ diffusion kinetics is effectively improved due to expanded cell parameters and O‐Li‐O slab spacing with the incorporation of large‐diameter Sr pillar ions, as revealed by X‐ray diffraction. As a result, the Sr/Zr‐modified NCM achieves a remarkable capacity retention of 99.4% after 200 cycles at 1 C, and a high rate capacity of 168.9 mAh g−1 at 10 C. This work opens new avenues to develop high‐performance NCM cathodes with high energy and high power for EVs with long calendar life.

3D Nanocomposite Thin Film Cathodes for Micro‐Batteries with Enhanced High‐Rate Electrochemical Performance over Planar Films

AbstractHigh energy and high power density rechargeable micro‐batteries are a necessity for powering the next generation of flexible electronics, internet of things, and medical technology devices. In theory, significant improvements in the capacity, current and power densities of micro‐batteries would result if 3D architectures with enhanced interdigitated component interface areas and shortened ion diffusion path‐lengths were used. Further gains are achievable if the materials utilized have high crystalline quality and are preferentially oriented for fast lithium intercalation. In this work, this is achieved by creating epitaxial thin film cathodes comprised of nanopillars of LiMn2O4 (LMO) embedded in a supporting matrix of electronically conducting SrRuO3 (SRO). The first electrochemical study of such a 3D vertically aligned nanocomposite (VAN) that displays clear cathode redox signatures is provided, and demonstrates remarkable capacity retention under high‐rate regimes. The electrochemical performance is shown to be dependent on the nanopillar topography, namely the crystallographic orientation, nanopillar dimensions, and electrode/electrolyte interfacial surface area. This work offers a pathway to realizing 3D architectured micro‐batteries with high‐capacity retention under high‐rate conditions enabling fast charge capabilities.