Energy Storage Materials最新文献

Li-CO₂/O₂ batteries present a promising strategy for CO₂ conversion and energy storage, yet the complexity of discharge products poses challenges for revealing their oxidation. Here, we simulate the influences of various properties of Li₂CO₃ and/or Li₂O₂ on the decomposition pathway by comprehensively analyzing the singlet O₂ (¹O₂) and gas components (O₂ and CO₂) generated during electrochemical oxidation. Our results show that no matter Li₂CO₃ or Li₂O₂, the decomposition of samples with small size and poor crystallinity produces less ¹O₂ and more gas product. Especially, small and poorly crystalline Li₂CO₃ triggers the concurrent decomposition of Li₂CO₃ and C, while large and highly crystalline Li₂CO₃ favors the solo decomposition pathway. Furthermore, the ¹O₂ yield can be most inhibited at a Li₂CO₃/Li₂O₂ ratio of 50%. After clarifying the nature of Li₂CO₃ and/or Li₂O₂ oxidation, the spatial distributions of the oxygen discharge product in Li-CO₂/O₂ batteries were observed by scanning transmission X-ray microscopy (STXM). Li₂CO₃ is mainly distributed in the interior of large aggregates with high crystallinity. Poorly crystalline Li₂O₂ appears as small particles or coats on the surface of Li₂CO₃. Combined with multi-dimensional information of the discharge products and simulation results, the oxidation behaviors of the discharge products in Li-CO₂/O₂ batteries are reacquainted.

Metamaterials, owing to their engineered building blocks, are considered as easily functionalized composites with designed nano-properties, sparking widespread research interest. However, the scalable synthesis and programmatically derived metamaterials into the designed nano-to-macro functionalized structure still pose significant challenges. Here, we report a fast and scalable synthesized Sn-guanine superstructures derived 1D porous carbonaceous metamaterial frameworks (Sn-NCS) that self-assembled by atomic Sn doping high nitrogen content carbon nanosheets. Due to the unique bottom-up designed nano-to-macro functionalized structural characteristics, Sn-NCS exhibited superior sodiophilic property. Using density functional theory (DFT) analysis and in-situ/ex-situ experimental characterization, we reveal that Sn-NCS can not only provide abundant Sn-N4 functional sites to minimize sodium nucleation overpotential and favors a uniform Na nucleation, but also effectively guide sodium deposition within the self-assembled porosity framework of Sn-NCS along the surface of carbon nanosheets to accommodate the volume variation and stress fluctuations within the anode, even under the extremely high current density of 120 mA/cm² with a deposition/stripping capacity of 20 mAh/cm². Moreover, the fabricated anode-sodium-metal-free sodium metal batteries (ASM-free SMB), using Cu-Sn-NCS (Sn-NCS coated Cu foil with a mass loading of 0.1 mg/cm²) as anodic current collector, exhibit highlighted energy density and excellent cycling reliability.

The aging of lithium-ion batteries (LIBs) is synergistically influenced by multiple chemical/mechanical degradation mechanisms. Therefore, conventional models that incorporate only partial mechanisms exhibit limited predictive accuracy and applicability, failing to fully reflect the effects of chemical/mechanical degradation under complex operating conditions. Here, we propose an aging model for NCM/C₆-Si LIBs coupled with comprehensive chemical/mechanical degradation mechanisms. The model includes chemical mechanisms at the C₆-Si anode solid electrolyte interface (SEI), Li plating, and NCM cathode electrolyte interface (CEI), as well as mechanical mechanisms of loss of active material (LAM) for C₆, Si, and NCM. Based on this model, we comprehensively investigate the effect of capacity loss by (dis)charge rates and ambient temperatures, obtaining the aging characteristics and the contribution of each mechanism to loss under different variables. Furthermore, we quantitatively analyze the sensitivity and response characteristics of the degradation sub-mechanism to (dis)charge rate and temperature. This study introduces an advanced aging analysis model for NCM/C₆-Si LIBs, which can effectively decouple the operational characteristics of the degradation mechanism and provide guidance for developing next-generation high-energy LIBs.

Conventional metallurgical technologies for recycling cathode materials from retired Li-ion batteries goes against carbon neutrality owing to massive material input and energy consumption. Although featuring with simplified process, direct regeneration technology still fails to bypass high-temperature driving forces for Li⁺ compensation of degraded cathodes. Herein, chemical re-lithiation strategy mediated by ferrocene is proposed to directly regenerate the Li-deficient spent cathodes. Ferrocene and its derivatives, the so-called p-type redox mediators, can be oxidized spontaneously from neutral molecules to stable cations under ambient conditions, allowing them to function as electron donors. Meanwhile, lithium salts serve as Li⁺ donors to ensure charge neutrality of the cathode lattice. The effects of solvation and substituent are thoroughly investigated to precisely regulate the potential of a series of ferrocene-based reductants. Chemical re-lithiation is driven thermodynamically by the intrinsic potential gap between ferrocene and degraded cathodes, thus fundamentally realizing a rapid lithiation reaction (taking less than 20 minutes at 25°C), while avoiding the involvement of high-temperature operation. Diverse characterizations have been performed to explored the Li⁺-electron concerted re-lithiation mechanism. The regenerated LiFePO₄ cathode demonstrated comparable Li⁺ storage capability to commercial cathode. Life-cycle analysis verifies the economical and environmental superiority of our chemical re-lithiation strategy to metallurgy in practical industry. The thermodynamically spontaneous chemical re-lithiation provides competitive options for greener recycling of retired batteries in the future.

The exceptional electrochemical oxidative stabilities of halide solid electrolytes (SEs) have led to extensive research on Li and Na all-solid-state batteries. In this study, we report a new K⁺ SE, cubic KTaCl₆, with a remarkable K⁺ conductivity of 1.0 × 10⁻⁵ S cm⁻¹, synthesized via a mechanochemical method. This value represents a 1000-fold enhancement over that of samples prepared through heat treatment, which is remarkable among halide K⁺ SEs reported to date. Through structural characterization via X-ray diffraction, Rietveld analysis, and bond valence energy landscape calculations, we reveal three-dimensional K⁺ migration pathways facilitated by face-sharing KCl₁₂¹¹⁻ cuboctahedra. This configuration is in contrast to that of the monoclinic KTaCl₆ produced through annealing, which features discontinuous K⁺ migration pathways. These pathways are formed by the edge- or corner-sharing of KCl₁₂¹¹⁻ anti-cuboctahedra, resulting in a significantly reduced K⁺ conductivity. Cyclic voltammetry measurements employing three-electrode cells indicate high electrochemical stability up to ≈3.7 V (vs. K/K⁺).

Dielectric capacitors, characterized by ultra-high power densities, have been widely used in Internet of Everything terminals and vigorously developed to improve their energy storage performance for the goal of carbon neutrality. With the boom of machine learning (ML) methodologies, Artificial Intelligence (AI) has been deeply integrated into the research and development of dielectric capacitors, including predicting material properties, optimizing material composition and structure, augmenting theoretical knowledge and so on. Through typical application cases, we comprehensively review that AI has greatly broadened the scope of the design and discovery of dielectric capacitors at multiple scales, ranging from atoms/molecules to domains/grains, films/bulks, and devices/systems. Finally, an outlook on potential solutions to current challenges and some novel applications and breakthroughs that AI may facilitate in the field of dielectric capacitors are highlighted.

All-solid-state batteries (ASSBs) have attracted considerable attention due to their high stability, offering a safer alternative to currently used batteries. Extensive research has been conducted to improve cathode part performance. However, the conventional hand mixing (HM) process results in inhomogeneous particle distribution, causing poor interparticle contact due to uneven stress distribution, and the solution process causes unwanted solid electrolyte (SE) deterioration when using a polar solvent although it ensures uniform SE distribution. To overcome these limitations, based on the design rule considering SE surface coverage of less than 100 %, we propose a cathode/SE composite, showing decent ionic/electronic conductivities, uniform SE distribution, and intimate interparticle contact, achievable through a mass-producible mechanical mixing (MM) process. Unlike the HM cell, the MM cell forms well-defined ionic percolating pathways and shows excellent structural stability. Consequently, the MM cell exhibits improved capacity retention during 1000 cycles and stable cyclability even under the harsh condition of 7 wt% SE. Finite element analysis theoretically demonstrates that uniform electrode and electrolyte currents are responsible for the improved performances including increased cathode utilization efficiency and reduced overpotentials. This study reveals the importance of composite design and uniform SE distribution in developing high-performance ASSBs at a practical cell level.