Energy Storage Density Research Articles

Design of Composite Cathode Electrodes for All-Solid-State Batteries

Li-ion batteries (LIBs) have high energy density and long-cycle energy storage; hence, they are widely used as power sources in electric devices. However, safety remains a major issue. Conventional LIBs developed using organic, liquid electrolytes may exhibit issues such as combustion and explosion. To address these issues, all-solid-state batteries (ASSBs) are considered promising candidates for advanced LIBs, offering high electrochemical stability and excellent safety owing to the non-flammability of the intrinsic inorganic solid electrolyte used1. The deployment of solid-state electrolytes (SSEs) into all-solid-state Li batteries is a promising approach due to the non-flammability and compatibility of SSEs with Li metal; thus, they have the potential to meet the increasing demands for high energy density and enhanced safety. Among the various SSEs, Li7La3Zr2O12 (LLZO) can be doped with Al, Ga, Ta, etc., to stabilize its cubic structure. LLZO exhibits high ionic conductivities (in the range of 10−4–10−3 S·cm−1), a wide operating voltage window, and excellent elastic and shear moduli. However, all ASSBs have solid-state electrode structures consisting solely of solid materials. As a result, Li-ion diffusion primarily occurs at the interfaces between the cathode-active material and solid electrolyte. Composite cathodes within ASSBs often exhibit numerous voids and high interfacial resistance. The limited ion conduction paths have constrained the electrochemical performance of ASSBs because of the inadequate contact areas between the active materials and solid electrolytes in the composite cathode2. To improve the electrochemical performance of ASSBs, some design issues of the composite cathode electrode need to be solved. The aim of this study is to enhance the performance of ASSBs using a bimodal garnet-type solid electrolyte, Li7La3Zr2O12 (LLZO), composed of electrolytes of two different sizes. The bimodal electrolyte composite cathode exhibits a higher density and fewer voids compared to the monomodal electrolyte, as the small powder particles fill the voids between the large ones.3 Finally, ASSBs prepared using the bimodal electrolyte achieve a low interface resistance and a large contact area between the solid electrolyte and the cathode material, resulting in enhanced electrochemical performance. Further details regarding the electrochemical and structural properties will be presented in the meeting.

Experimental and Theoretical Study of the Performance of Li-Oxygen Batteries with Multiwall Carbon Nanotube Cathodes

Although Li-oxygen batteries with organic electrolyte have a theoretical energy density of 3505 kWh/kg (which is comparable to the energy density of gasoline), in practice only a fraction of this energy density has been demonstrated. Despite this gap, Li-oxygen batteries remain to have a great potential to replace the current energy storage devices in applications requiring light power sources such as portable electronic devices, unmanned aerial vehicles, and renewable energy storage. There is great interest in seeing if Li-oxygen batteries, which have the potential to have a far higher gravimetric energy storage density than any other battery chemistry, can be developed to power electric vehicles (EVs) and allow for driving ranges that are comparable to those of gasoline-powered cars [1]. In this presentation we make a combined experimental and theoretical investigation of the performance of the Li-oxygen batteries for different cathode structures, assembling technique (that can induce different concentrations of seeds available for precipitation and growth in the cathode) and discharge conditions. The theoretical model is based on the traditional drift-diffusion approach, coupled with a simple model that describes the precipitation and growth of lithium peroxide on the carbon nanotubes. The model also predicts that it is optimum to use variable porosity cathodes (with higher porosity on the oxygen side and lower porosity on the separator side) in order to maximize the energy density of these cells, a fact which is also demonstrated using our experimental data. More details about the mathematical approach and a comparison with the experimental data will be presented at the conference.[1] N. Imanishi and O. Yamamoto, “Perspectives and challenges of rechargeable lithium–air batteries,” Mater. Today Adv., vol. 4, p. 100031, Dec. 2019, doi: 10.1016/j.mtadv.2019.100031.

(Invited) A Non-Stabilized Supersaturated High-Energy-Density Storage Concept for the Redox Flow Battery and Its Demonstration in an H2-V System

Redox flow battery (RFB)-based storage systems have the unique feature of separating power generation from energy storage, allowing individually sized systems uncoupling power from capacity. RFBs can be used for days-long energy storage, but because of the low solubility of most ions and molecules in both aqueous and non-aqueous solvents,[1,2] scaling these RFB systems for days-long applications requires significant storage tanks and floor area.Our team has been working on a new storage method for Vanadium electrolytes that significantly increases the energy storage density while still maintaining the traditional flow battery design.[3] This method involves storing the reactants as both soluble ions and as undissolved solids, only allowing liquid-containing soluble ions to circulate through the battery. To achieve this, a solid form of Vanadium salt must be precipitated within the storage tanks, with an applied temperature swing to dissolve this solid and keep the electrolyte below saturation level for transport to the flow battery. To run this system without any form of external heating or cooling, we propose to allow saturated electrolyte to enter the flow battery during operation. This presentation will discuss the operation of a V-H2 redox flow battery system operating at 2.5 M total vanadium concentration (above the 1.8M solubility limit of VOSO4)[4] and its comparison to a more traditional sub-saturated system at 2.5M and 1.5M total vanadium ion concentrations respectively.

(Invited) Study on the Effect of Additive in High Nickel NMC – Graphite Libs for HF- Scavenging and Stabilization of Cei Layer

Lithium ion batteries have been marked by steady progress over the past few decades owing to their high volumetric and gravimetric energy storage densities. The advent of LIBs resulted in the consistent shift of automotive industry towards hybrid EV's and BEV's. The Nissan Leaf, introduced in December 2010, became the first modern all-electric, zero tailpipe emission five door family hatchback to be produced for the mass market from a major manufacturer. Nissan has made constant efforts in improving the existing LIBs.With the advent of new high nickel cathode materials there has been an improvement in the energy density of LIBs and the ability to internalize the material supply chain. However, these cathode materials induce additional challenges due to instability of cathode electrolyte interface and dissolution of transition metals in the systems.[1-4]In the current work, electrolyte additive has been explored for stabilizing the cathode surface by stabilizing the cathode electrolyte interface in NMC811 and Graphite system in carbonate electrolyte system. The cycling data was analyzed with different capacity vs voltage and/current to identify the effect of additive and cycling degradation on the reaction kinetics and potentials. A methodology involving Distribution of Relaxation time (DRT) analysis, equivalent circuit design and electrochemical impedance fitting was developed to identify the different electrochemical components of the cell and their contribution towards the increase in internal resistance. The analysis was conducted during formation cycles and at different checkpoints for long cycling scenarios. The contribution of cathode and anode resistances were deconvoluted for the mixed impedance signal. Furthermore, XPS and TEM analysis were used to verify different features of the cathode and anode wherever applicable and feasible, to study the effect of the additive. Cui, Z., & Manthiram, A. (2023). Thermal Stability and Outgassing Behaviors of High‐nickel Cathodes in Lithium‐ion Batteries. Angewandte Chemie International Edition, 62(43), e202307243.Yu Wu, Xiang Liu, Li Wang, Xuning Feng, Dongsheng Ren, Yan Li, Xinyu Rui, Yan Wang, Xuebing Han, Gui-Liang Xu, Hewu Wang, Languang Lu, Xiangming He, Khalil Amine, Minggao Ouyang, Development of cathode-electrolyte-interphase for safer lithium batteries, Energy Storage Materials, Volume 37, 2021, Pages 77-86, ISSN 2405-8297.Hou, J., Lu, L., Wang, L. et al. Thermal runaway of Lithium-ion batteries employing LiN(SO2F)2-based concentrated electrolytes. Nat Commun 11, 5100 (2020).Yu Wang, Xuning Feng, Yong Peng, Fukui Zhang, Dongsheng Ren, Xiang Liu, Languang Lu, Yoshiaki Nitta, Li Wang, Minggao Ouyang, Reductive gas manipulation at early self-heating stage enables controllable battery thermal failure, Joule, Volume 6, Issue 12, 2022, Pages 2810-2820,ISSN 2542-4351.

Multifunctional Layer Coated Cu for Anode-Free Lithium Metal Batteries

Anode free lithium metal battery (AFLMB) is one of the alternate choices and new system for high energy density storage system because it has no active anode material initially. In addition, the fabrication of AFLMB is simple, low-cost, safe since Li metal or other active anode material is not directly used as an anode. The energy density of AFLMB will be significantly larger, by more than ~50% relative to conventional LIBs. Since the Li amount is limited and electrolyte decomposition, consuming Li during the SEI formation, the capacity can fade quickly relative to LMB. However, AFLMB is not only provide the highest energy density but the best system to understand the interfacial phenomena [1-3] and the effectiveness of the approaches to improve cell performances of LMBs [4-8]. In this talk, I will present our multifunctional layer coating approaches to improve the cell performance of anode-free lithium metal batteries. Keywords: Multifunctional Layer Coating; Anode-free; Lithium; Coulombic efficiency; Capacity Retention

Aliovalent doping engineering to synergistically optimize the energy storage properties of Sr0.7Bi0.2TiO3-based linear-like relaxor ferroelectric ceramics

Dielectric capacitors with high energy storage density and power density are essential for the miniaturization and lightweight design of electronic devices. However, current applications are hampered by the challenge of simultaneously achieving high recoverable energy storage density and efficiency, as well as the fact that many dielectric energy storage ceramics contain lead elements. In this study, a multiple optimization strategy is proposed to significantly increase the breakdown strength while maintaining a high polarization strength by forming Bi3+-Li+ defect pairs to disrupt the paraelectric phase, and by introducing aliovalent double ions Li+ and La3+ to increase the cationic disorder. The change of domain structure and the relaxation enhancement mechanism is analyzed by dielectric properties and first-order reversal curve. Band gap, impedance and numerical simulations reveal the breakdown strength enhancement mechanism. As a result, the ceramics achieve a remarkable combination of high Wrec of 4.4 J/cm3 and high ƞ of 90 % at 420 kV/cm. Furthermore, the ceramic exhibits exceptional stability and fatigue resistance. Notably, the ceramic obtains a power density of 99.5 MW/cm3 and a rapid discharge rate of 0.22 µs. These findings demonstrate the excellent potential of Sr0.7Bi0.2TiO3-based ceramics as an alternative to Pb-based ceramics, and provide an effective strategy for developing advanced energy storage materials.

Superior dielectric temperature stability and high energy-storage density of ecologically friendly 0.7(0.94Bi0.5Na0.5TiO3–0.06BaTiO3)-0.3Ba(Mg1/3Ta2/3)O3 ceramics

Recently, much attention has been given to dielectric ceramic capacitors, which have excellent temperature stability and a high energy-storage density. Ecologically friendly ceramics ((1-x)(0.94Bi0.5Na0.5TiO3–0.06BaTiO3)-xBa(Mg1/3Ta2/3)O3, where x = 0, 0.15, 0.2, 0.25, or 0.3) were synthesised using a conventional solid-state method. The ceramic sample with x = 0.3 exhibited a superior dielectric temperature stability, relative permittivity that varied within ±15%, and low dielectric loss of less than 0.02 over a temperature range of −100 to +307 °C, which met the X9R specifications. In addition, a scanning electron microscopy image confirmed that the sample had a dense and uniform microstructure. Furthermore, a high recoverable energy-storage density of 6.75 J/cm3 was obtained for the ceramic sample with x = 0.3 under a moderate applied electric field of 420 kV/cm. These characteristics suggest that it is a promising candidate for an ecologically friendly temperature-insensitive dielectric ceramic for energy-storage capacitors.

Investigation and optimization of the thermal performance of compressed supercritical CO2 energy storage system based on dynamic modeling and transient simulation

Compressed CO2 energy storage is a new type of energy storage with high energy storage density and a compact structure. Understanding the system's dynamic operational characteristics is crucial for optimizing parameters and developing control strategies. We established two dynamic compressed supercritical CO2 energy storage systems (SC-CCESs) without additional cold and heat sources and simulated their performance under design conditions. The results show that the single-stage system outperforms the double-stage system. The single-stage system is simulated from design conditions to periodic dynamic operating conditions. Energy and exergy analyses of the single-stage compression system were conducted, confirming that the model aligns with the first and second laws of thermodynamics. The dynamic behavior of the compressor, turbine, and storage tanks was analyzed, and a sensitivity analysis of key system parameters was performed. After optimization, the system's RTE improved to 63.35 %, a 3.09 % points increase, and the exergy loss decreased by 10.37 % points.

A new dynamic control strategy for a solar-driven absorption thermal energy storage system: Modeling and performance evaluation

Solar heating is a vital technology to promote the decarbonization of building energy supply systems. However, the mismatch between the intermittency of solar energy supply and the fluctuating heating demands poses significant challenges to its application. Current heat storage systems often exhibit low energy density, significant heat losses, and limited temperature regulation capabilities, which restrict their effectiveness in practical applications. This paper proposed a new real-time control strategy for a solar-driven absorption thermal energy storage system, integrated with an absorption heat pump, which can resolve the mutual constraints between solar energy utilization efficiency and the heating temperature, and then improve the system flexibility. The dynamic control strategy is implemented to manage concentration and temperature by regulating the inlet and outlet flow rates of three tanks, namely the absorbate tank, the weak solution tank, and the strong solution tank. A thermodynamic model is developed based on Aspen Plus and Matlab. Results show that within a 24-hour cycle, the system, driven by intermittent solar energy, can effectively meet the varying user-side heating demands through flow rate regulation. An optimized tank design, based on flow variation analysis, reduces the total volume by approximately 35 %. Additionally, the system can recover low-grade heat from the environment through the absorption heat pump, achieving an energy storage efficiency of 1.07 and an energy storage density of 56.13 kWh/m3. The proposed system and its dynamic control method are well-suited to intermittent solar energy, increasing the system flexibility, and thus expanding renewable energy utilization potential, especially those involving multi-energy complementary systems.

Room temperature superparaelectric state in 20BaTiO3-60V2O5-20Bi2O3 glass for capacitive energy storage applications

Materials with high dielectric constant exhibit excellent charge storage capacity, making them favorable solutions for next-generation dielectric capacitors. The glass system with the composition of 20BaTiO3-60V2O5-20Bi2O3 was prepared by conventional melt quenching technique. The glassy nature of the sample was confirmed by using DSC and XRD measurement while the existence of nano polar cluster inside the glass matrix was confirmed using HRTEM. The real permittivity (ε\\) value shows two peaks in which the dielectric constant gradually increases up to a maximum value (εm) with the increase in temperature, and then it smoothly decreases, suggesting two phase transitions around 180 and 280 ◦ C. The measurements of the P–E hysteresis loop illustrated energy storage density of 124 mJ/cm3 and energy storage efficiency about 84% at room temperature. The glass sample shows superparaelectric behavior confirmed by the dielectric and P-E loop measurements. For high-energy storage applications, dipolar glasses have more outstanding potential than conventional ceramic dielectrics. Eventually, the glass matrix maintains high breakdown strength and can effectively stabilize nanocluster phases. So, we consider the present glass sample to be a good candidate for capacitive energy storage applications.

PbZrO3-based thin film capacitors with high energy storage efficiency

Antiferroelectric (Pb0.87Sr0.05Ba0.05La0.02)(Zr0.52Sn0.40Ti0.08)O3 thin film capacitors were fabricated for dielectric energy storage. Thin films with excellent crystal quality (FWHM 0.021°) were prepared on (100) SrRuO3/SrTiO3 substrates by pulsed laser deposition. The out-of-plane lattice constant of the thin film was 4.110 ± 0.001 Å. An average maximum recoverable energy storage density, 88 ± 17 J cm−3 with an efficiency of 85% ± 6% at 1 kHz and 80 ± 15 J cm−3 with an efficiency of 91% ± 4% at 10 kHz, was achieved at room temperature. The capacitor was fatigue resistant up to 106 cycles at an applied electric field of 2 MV cm−1. These properties are linked to a low level of hysteresis and slow polarization saturation. PbZrO3-derived oxide thin film capacitors are promising for high efficiency and low loss dielectric energy storage applications.

Simultaneous achievement of high energy storage density and ultrahigh efficiency in BCZT-based relaxor ceramics at moderate electric field

The development of high-performance energy storage dielectric materials is the key to the development of large capacity ceramic capacitor. How to obtain the high energy storage density and efficiency of dielectric materials is the basis. Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) has high energy storage potential as a typical piezoelectric material, but it shows poor energy storage properties due to low breakdown electric field and large remnant polarization. In this work, we propose a combined optimization strategy aimed at enhancing the comprehensive energy storage performance of BCZT-based ceramics through doping with bismuth-based oxides. The diverse phase morphology offers substantial potential for modifying the electrical properties of BCZT-based ceramics. Electrical homogeneity is markedly improved with the incorporation of Bi2/3(Al1/2Nb1/2)O3 (BAN), which is accompanied by a reduction in long-range ferroelectric phases and the emergence of polar nanoregions. Ultimately, optimal BCZT-xBAN ceramics with x = 0.09 exhibit superior energy storage performances (Wrec ∼ 3.71 J/cm3, η ∼ 94.54 %) under moderate electric fields. Furthermore, BCZT-0.09BAN ceramics demonstrate commendable fatigue endurance, frequency stability, and temperature stability characteristics; notably achieving an ultrafast discharge rate of t0.9–14.6 ns alongside excellent discharge properties (CD ∼ 1278.66 A/cm2, PD ∼ 191.80 MW/cm3, WD ∼ 1.57 J/cm3).

Enhanced energy storage performance of lead-free Sr0.7Bi0.2TiO3 ceramics via tape casting

Abstract The development of pulsed power technology demands high energy storage density dielectric materials. In this study, Sr0.7Bi0.2TiO3 relaxor ferroelectric (rFE) ceramic thick films were prepared using a tape-casting process. The ceramics exhibit a dense structure and typical rFE hysteresis curves, achieving an energy storage density of 4.77 J cm−3 and efficiency of 94.4%, attributed to the high polarization intensity, low remnant polarization, and low hysteresis loss of rFE. Additionally, the material demonstrates good temperature stability. Moreover, the Sr0.7Bi0.2TiO3 ceramic thick films show advantages in charge-discharge performance, capable of discharging within hundreds of nanoseconds and achieving a power density of 137 MW cm−3. Overall, the Sr0.7Bi0.2TiO3 ceramic thick film exhibits a comprehensive performance advantage in terms of energy storage density, efficiency, and power density. Additionally, the material was fabricated using the tape-casting process, which is compatible with subsequent multilayer ceramic capacitor production, indicating potential for further performance enhancement.

Double enhancement of energy storage density in relaxor ferroelectric 0.8BaTiO3-0.2BiScO3 by Li defect-regulated strategy

To meet the ever-increasing demands for pulsed power technologies, the development of lead-free dielectric ceramics with a large energy storage density (Wrec) and high energy storage efficiency (η) is crucial for enhancing the electrical performance of power capacitive devices. The conventional solid-solution, while effective in suppressing long-range order and improving energy storage performances, often results in a reduction of maximum polarization. This reduction necessitates the application of a larger electric field to obtain a relatively high Wrec. Herein, an effective strategy to enhance Wrec again via inducing Li-related defect dipoles is proposed. By introducing (Bi0.5Li0.5)TiO3 into 0.8BaTiO3-0.2BiScO3 matrix, the polarization contribution from defect dipoles together with intrinsic polarization induces an at least two-time enhancement in Pmax. Our findings indicate ∼62.9 % enhancement in the Wrec of 0.8BT-0.2BS, elevating from 2.56 J cm−3 to 4.17 J cm−3 at electrical field of 300 kV cm−1, while preserving an energy storage efficiency of 90.35 %. Furthermore, it also exhibits good thermal stability with the variations of ΔWrec < 3 % and η< 5 %. This research introduces a novel strategy for defect regulation strategy in the design of high-performance dielectric materials, which is expected to expedite the optimization of the advanced energy storage capacitors.

Enhanced energy storage performance of NaNbO3-based ceramics by modifying phase structures and electrical insulation

The remarkable polarization and stability of ceramic capacitors make them promising candidates for pulse-power devices in energy-storage systems. However, the energy-storage density of ceramic capacitors is severely limited by the negative correlation between the maximum polarization (Pm) and the breakdown strength (BDS), leading to the impediment of broader applications. Herein, we reconcile the contradiction by synthesizing high-performance NaNbO3-based ceramics via chemical doping with Bi(Ni0.5Ti0.25Zr0.25)O3 (BNTZ). An antiferroelectric-paraelectric phase transition with a decline in polarization hysteresis is induced by the dopant. Further studies have shown that the existence of a tiny quantity of the polar phase in the nonpolar matrix contributes to a higher Pm, and the enhancement of both electrical resistivity and activation energy of the conductance also improved their BDS. The thinning process is also identified to be important in the improvement of its BDS and Wrec, resulting in the maximum energy-storage density of 3.53 J/cm3 with an energy efficiency of 74.2 % in thinned 10 mol% BNTZ-doped NaNbO3 samples. Our findings provide a feasible approach to simultaneously improving energy-storage density and efficiency in NaNbO3-based ceramic capacitors.

Rational Strategies for Preparing Highly Efficient Tin-, Bismuth- or Indium-Based Electrocatalysts for Electrochemical CO2 Reduction to Formic acid/Formate.

Electrochemical carbon dioxide reduction reaction (CO2RR) is an environmentally friendly and economically viable approach to convert greenhouse gas CO2 into valuable chemical fuels and feedstocks. Among various products of CO2RR, formic acid/formate (HCOOH/HCOO-) is considered the most attractive one with its high energy density and ease of storage, thereby enabling widespread commercial applications in chemical, medicine, and energy-related industries. Nowadays, the development of efficient and financially feasible electrocatalysts with excellent selectivity and activity towards HCOOH/HCOO- is paramount for the industrial application of CO2RR technology, in which Tin (Sn), Bismuth (Bi), and Indium (In)-based electrocatalysts have drawn significant attention due to their high efficiency and various regulation strategies have been explored to design diverse advanced electrocatalysts. Herein, we comprehensively review the rational strategies to enhance electrocatalytic performances of these electrocatalysts for CO2RR to HCOOH/HCOO-. Specifically, the internal mechanism between the physicochemical properties of engineering materials and electrocatalytic performance is analyzed and discussed in details. Besides, the current challenges and future opportunities are proposed to provide inspiration for the development of more efficient electrocatalysts in this field.

Ultra-stable dielectric properties and enhanced energy storage density of BNT-NN-based ceramics via precise core-shell structure controlling

High discharge-energy-storage-density (Wdis) at low electric field is in high demand for advanced ceramics. In this work, a core-shell structure is well constructed and meticulously adjusted to enhance the energy storage properties. The meticulous control of the coating layer can effectively improve the breakdown strength (Eb), ensure a high polarization, and achieve a significant optimization of temperature stability, simultaneously. Compared with 0.78Bi0.5Na0.5TiO3-0.22NaNbO3 (BNTNN) ceramics without coating layer, the BNTNN@0.8 wt%SiO2 ceramics achieve an inspiring improvement of 50 % in Eb, which is benefit from the finer grains and the enhanced band gap. Notably, the BNTNN@0.8 wt%SiO2 ceramics obtain a superior Wdis of 6.17 J/cm3 at 330 kV/cm. Importantly, BNTNN@0.8 wt%SiO2 ceramics display an ultra-stable temperature stability with a high dielectric of 1350 ± 2.5 % over a wide temperature range from 35 to over 400 °C. The meticulous control of core-shell structure is expected to be a general and effective way to improve the energy-storage performance of diverse dielectric ceramics.

Improving energy storage density, piezoelectric, and energy harvesting performances of eco-friendly (Bi0.49−xBaxLa0.01Na0.40K0.10)TiO3 ceramics by composition design strategy

Improving energy storage density, piezoelectric, and energy harvesting performances of eco-friendly (Bi0.49−xBaxLa0.01Na0.40K0.10)TiO3 ceramics by composition design strategy

Enhanced thermochemical heat storage performance of CaO/CaCO3 via pyroligneous acid impregnation and Co/Mn co-doping

Calcium-based thermochemical heat storage (TCHS) is an economical and environmentally friendly technology for efficient heat storage. It can strengthen the flexibility in power systems of renewable energy and promote the recovery and storage of waste heat in energy-intensive industries. However, CaO/CaCO3 is extremely prone to sintering at operational temperatures. Consequently, a cost-effective approach was proposed to synthesize calcium-based TCHS materials modified by pyroligneous acid (PA) impregnation and co-doping with dual transition metals. The heat storage performance, physicochemical property, and anti-sintering mechanism of synthesized CaO were comparatively examined. The sample prepared with a molar ratio of Ca: Co: Mn = 100:3:7 (PACa-Co3Mn7) exhibited an initial energy storage density of 1.76 MJ/kg, which gradually rose to 1.88 MJ/kg. After 20 cycles, the value decreased by only 4.39 % from its peak, indicating outstanding TCHS performance. Characterization results indicated that the specific surface area and pore volume of PACa-Co3Mn7 were 10.48 m2/g and 0.035 cm3/g, which were 2.34 and 2.69 times those of CaO stemmed from the calcination of limestone, respectively. The fruitful pores provided pathways for CO2 diffusion within the CaO particles or CaCO3 product layer. The uniformly distributed Co and Mn elements combined to form Ca3CoMnO6. Ca3CoMnO6 could serve as the inert carrier that mitigated the grain-growth of CaO, thereby stabilizing the pore structure and resisting the sintering of PACa-Co3Mn7. Furthermore, density functional theory (DFT) calculations demonstrated that the free Mn and Co elements efficiently promoted the electrons transfer between CaO and CO2, which improved the reactivity of PACa-Co3Mn7. Therefore, CaO modified by PA impregnation and co-doping with dual transition metal is a promising candidate for the TCHS system.

Ultra-high energy storage efficiency achieved through the construction of interlocking microstructure and excitation of depressor effects

Glass-ceramic capacitors struggle to balance high energy storage efficiency (η>90 %) and sufficient breakdown field strength (Eb), hindering their use in energy storage. Interface polarization, caused by the accumulation of free charge, reduces breakdown strength. We prepared glass-ceramic materials with varying contents of the glass phase using traditional melting techniques, adjusting the glass content to enhance an interlocking structure between the glass and crystal phases, reducing Interface polarization. Divalent metal oxide BaO in the glass stimulated a depressor effect, filling gaps and increasing resistivity. The optimal composition (x = 0.2) achieved a 95 % energy storage efficiency and an energy storage density of 4.4 J/cm3 at 680 kV/cm, while x = 0.25 reached an ultra-high energy storage efficiency of 99 %. Increasing glass content reduced activation energy for Interface polarization (Ei) from 1.27 eV to 1.08 eV. Samples with x = 0.2 exhibited low dielectric loss (∼0.005), high dielectric constant (∼142), ultra-high power density (∼52.8 MW/cm3), and ultra-fast discharge speed (∼26 ns), suggesting future potential for high-performance glass-ceramic materials.