Cathode Applications Research Articles

Artificially transformed ultra-stable Li6.75La3Zr1.75Ta0.25O12 incorporated composite solid electrolyte towards high voltage solid lithium metal batteries

Garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) is enlightening great future in solid-state lithium metal batteries due to the considerable ionic conductivity and good compatibility with metallic lithium. Unfortunately, LLZTO is always trapped into the Li2CO3 by-product forming on the surface in a moist atmosphere and becomes difficult for practical application. Herein, we propose an in-situ conversion from the Li2CO3 by-product towards electrochemical active LiCoO2 to turn this disadvantage. The modified LLZTO (M−LLZTO) realizes excellent air stability and performs impressively enhanced electrochemical performance in the structure application of both cathode and composite solid electrolyte (CSE). The prepared CSE delivers high ionic conductivity and good electrochemical stability against Li metal with an ultra-long lifespan over 2000 h in the symmetrical cells. Once working in a solid-state lithium battery with a LiCoO2 cathode, the solid battery maintains a low capacity fade of 4.51 % over 150 cycles and a high average columbic efficiency of 99 %. All these results promise a new insight into the air sensitive solid electrolyte for advanced solid-state lithium batteries.

Ca-Fe co-doped La0.75Sr0.25Cr0.5Mn0.5O3 cathodes with high electrocatalytic activity for direct CO2 electrolysis in solid oxide electrolysis cells

Solid oxide electrolysis cell (SOEC) is a promising electrochemical device for effectively and sustainably converting CO2 into CO, and the development of SOEC depends on the exploitation of appropriate cathodes with good catalytic activity and stability. La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM)-based cathodes have been widely studied due to the excellent redox stability and good compatibility with other components of SOEC. La0.75Sr0.2Ca0.05Cr0.5Mn0.5O3 (LSCCM) fabricated in our previous work shows a relatively satisfying electrocatalytic performance and is expected to be further optimized. Herein, Fe-doped LSCCM, La0.75Sr0.2Ca0.05Cr0.5Mn0.5−xFexO3 (LSCCMFex, x = 0, 0.05, 0.1, 0.15, denoted as LSCCM, LSCCMFe5, LSCCMFe10, and LSCCMFe15, respectively) materials, are investigated as the cathodes for direct CO2 electrolysis in SOEC. Specifically, LSCCMFe5 material shows a good chemical compatibility with Gd0.1Ce0.9O2-δ (GDC) electrolyte and excellent chemical stability in 30% CO/CO2 atmosphere. Compared with the LSCCM electrode, the LSCCMFe5 cathode presents 30.5% decrease in polarization resistance for a half cell under pure CO2 atmosphere at 800 ℃ and 42.3% increase in current density (0.60 A cm−2) for the direct CO2 electrolysis of a single cell with an applied voltage of 1.6 V at 800 ℃. LSCCMFe5 exhibits a high electrocatalytic activity among various LSCM-based cathodes. The improvement in electrocatalytic performance could be due to the enhanced chemical adsorption of CO2 and increased highly active O-/O22- species related to the newly generated oxygen vacancy via Fe-doping, leading to favorable surface reaction kinetics. Moreover, no degradation could be observed for the single cell after the direct CO2 electrolysis test up to 100 h, suggesting an attractive competitiveness for the application of Fe-doped LSCCM cathodes to SOECs.

Regenerable sensor based on tris(4,7′-diphenyl-1,10-phenanthroline)ruthenium (II) for anodic and cathodic electrochemiluminescence applications

Tris(4,7′-diphenyl-1,10-phenanthroline) ruthenium (II) dichloride [Ru(dpp)32+] was used for the first time to construct a regenerable electrochemiluminescence (ECL) sensor. The Ru(dpp)32+-modified carbon paste electrode (CPE) showed several unique features in comparison with commonly studied Ru(bpy)32+-modified electrodes. On the one hand, a quite reversible reduction peak was observed at −0.96 V where no obvious hydrogen evolution occured, enabling the sensitive detection of S2O82−. Moreover, our proposed S2O82− sensor showed a good linear range from 3 × 10−9 to 3 × 10−4 M with a detection limit of 2 nM, indicating higher sensitivity for the same analyte than previously reported ECL methods by about two orders of magnitude. On the other hand, the Ru(dpp)32+-modified electrode showed an irreversible oxidation peak because electrogenerated Ru(dpp)33+ is very reactive in aqueous solutions, while Ru(bpy)32+-modified electrode showed a reversible oxidation peak. Moreover, the present sensor showed a good linear range from 10−7 M to 10−3 M for oxalate with a detection limit of 60 nM. It detected oxalate in urine samples with nice recoveries. The regenerable ECL sensor presented good characteristics, such as low cost, simple fabrication procedure and fast response time. The Ru(dpp)32+ based regenerable sensor is an attractive alternative to Ru(bpy)32+-based regenerable sensor, as it can be used for both anodic and cathodic ECL analysis with high sensitivity in aqueous media.

Uncovering Molecular Structure – Redox Potential Relationships for Organic Electrode Materials: A Hybrid DFT – Machine Learning Approach

Density functional theory and machine learning are used to investigate the structure-electrochemical performance relationships of organic moieties for use in Li-ion batteries. Namely, DFT calculations are performed to predict the redox potential of several novel organic molecules with an accuracy within ~0.1 V of experimental measurements. However, despite its ability to provide valuable insight regarding the electrochemical properties of novel organic molecules, our high efficacy DFT modeling protocol demands significant computational time and is therefore impractical for the vast screening of novel material candidate. As a result, we explore machine learning as a strategy for the accelerated discovery of novel organic materials. More critically, we use machine learning as a method for assessing the various structure-electrochemical relationships which can provide a more general guideline for the design of organic electrode materials. We are employing different learning models, including artificial neural networks, gradient-boosting regression, and kernel methods (such as kernel ridge regression and Gaussian process regression), via three different pipelines with varying sophistication with the aim of generating an advanced ML scheme for the accurate prediction and analysis of electrochemical activity. In addition to incorporating structural fingerprints, we are exploring an active learning framework, namely using the efficient global optimization scheme, to explore the materials space strategically using publicly available datasets. Through this approach, we can discover new electrode materials that could 1) have a higher probability for achieving enhanced electrochemical properties and 2) increase our learning model’s performance by increasing our dataset’s representation of the material space. Additionally, we are implementing a high-throughput virtual screening (HTVS) pipeline which consists of several surrogate learning models with increasing levels of fidelity. The material candidates are pruned at each stage to discard samples that are unlikely to possess a desirable redox potential for cathodic application, and the remaining samples move on to the next model. In this way, only a subset of the original dataset which has a higher probability for lying within the desired redox potential range is pursued using the most computationally expensive model.

Carbonaceous-Material-Induced Gelation of Concentrated Electrolyte Solutions for Application in Lithium-Sulfur Battery Cathodes.

Lithium-sulfur (Li-S) batteries can theoretically deliver high energy densities exceeding 2500 Wh kg-1. However, high sulfur loading and lean electrolyte conditions are two major requirements to enhance the actual energy density of the Li-S batteries. Herein, the use of carbon-dispersed highly concentrated electrolyte (HCE) gels with sparingly solvating characteristics as sulfur hosts in Li-S batteries is proposed as a unique approach to construct continuous electron-transport and ion-conduction paths in sulfur cathodes as well as achieve high energy density under lean-electrolyte conditions. The sol-gel behavior of carbon-dispersed sulfolane-based HCEs was investigated using phase diagrams. The sol-to-gel transition was mainly dependent on the amount of the carbonaceous material and the Li salt content. The gelation was caused by the carbonaceous-material-induced formation of an integrated network. Density functional theory (DFT) calculations revealed that the strong cation-π interactions between Li+ and the induced dipole of graphitic carbon were responsible for facilitating the dispersion of the carbonaceous material into the HCEs, thereby permitting gel formation at high Li-salt concentrations. The as-prepared carbon-dispersed sulfolane-based composite gels were employed as efficient sulfur hosts in Li-S batteries. The use of gel-type sulfur hosts eliminates the requirement for excess electrolytes and thus facilitates the practical realization of Li-S batteries under lean-electrolyte conditions. A Li-S pouch cell that achieved a high cell-energy density (up to 253 Wh kg-1) at a high sulfur loading (4.1 mg cm-2) and low electrolyte/sulfur ratio (4.2 μL mg-1) was developed. Furthermore, a Li-S polymer battery was fabricated by combining the composite gel cathode and a polymer gel electrolyte.

High-rate Ni-rich single-crystal cathodes with highly exposed {0 1 0} active planes through in-situ Zr doping

Nickel (Ni)-rich cathodes with high energy density will play a crucial role in the rapidly growing electric vehicles sector. However, the large-scale application of Ni-rich cathodes is still limited by structural instability and severe capacity decay. Even though the construction design of single-crystal cathodes alleviates these defects, the sluggish lithium ion (Li+) diffusion between the larger single-crystal particles restricts its rate performance. We propose an in-situ zirconium (Zr) ion doping strategy to modulate the primary particle morphology of precursors and achieve their corresponding single-crystal cathodes with highly exposed {010} planes. The high percentage of {010} planes will deliver more Li+ diffusion channels and improve the transportation kinetics. Moreover, the homogeneous doping of Zr inside the bulk phase will significantly suppress the anisotropic shrinkage of c-axis and maintain an intact internal structure, thus preventing the accumulation of rock-salt phases. As a result, the Zr-doped single-crystal cathode exhibits excellent cycling stability, whether at 25 ℃ or 45 ℃. More importantly, the rate performance of cathodes has been remarkably enhanced after Zr modification. At the ultra-high rate of 10 C, it can maintain a high specific capacity of 121.4 mAh g−1 (81.8 % of capacity retention) after 250 cycles in the 3.0–4.3 V range.

3D Cellulose Graphene Aerogel with Self‐Redox CeO2 as Li2S Host for High‐Performance Li–S Battery

Lithium sulfide is considered the promising cathode material of a Li–S battery because of its high theoretical capacity, high melting point, affordable volume expansion, and lithium composition. However, the quick capacity fading and high activation energy barrier due to low electronic and ionic conductivity and polysulfide shuttle effect still restrict the practical application of the Li2S cathode. Herein, CeO2 is introduced with unique self‐redox characteristics into cellulose graphene aerogel (CGA) with the 3D interconnected structure (CGA/CeO2) as the host of Li2S. It is found that CGA/CeO2 can provide plentiful three‐phase boundary for the chemisorption to LiPSs through the strong polarity of CeO2. Moreover, the ultrastrong polarity of CeO2 can restrain the LiPSs shuttle, and CeO2 can spontaneously oxidize polysulfide, thus boosting the conversion reaction kinetics and comprehensive electrochemical performances of Li–S battery based on Li2S cathode. As a result, these features reciprocate Li2S‐CGA/CeO2 cathode excellent electrochemical performances. Therefore, this work not only provides a significant exploration for the mechanical explanation of the cerium oxide catalytic conversion reaction but also provides a brand‐new idea for the excellent electric catalyst for the catalytic conversion reaction of polysulfide in lithium–sulfide batteries.

Integrated Modification Strategy Enables Remarkable Cyclability and Thermal Stability of Ni-Rich Cathode Materials for Lithium-Ion Batteries

Structural degradation and surface chemical instability are dominant issues of Ni-rich layered cathodes, which trigger capacity fading and safety concerns, hindering the extensive application of Ni-rich cathodes toward high-energy, long-life lithium-ion batteries. Here, by combining trace Ta doping and an ultrathin Zr-Y mixed oxide coating, an integrated modification strategy significantly improves the cycling and thermal stability of Ni-rich LiNi0.88Co0.10Al0.02O2 (NCA) cathodes. The integrated modified Ni-rich cathode provides an unprecedented comprehensive performance with a high discharge capacity of 212.2 mA h g-1 at 0.1 C, an 88.6% cycling retention after 500 cycles at 1 C, and a high exothermic peak temperature of 261 °C compared with the pristine NCA cathode (67.4% capacity retention for 500 cycles and 221 °C for the exothermic peak). Further mechanism studies illustrate that a dual-structural surface constructed of a rock salt surface induced by Ta doping and ultrathin Zr-Y mixed oxide coating jointly suppresses surface side reactions between cathodes and electrolytes. Moreover, trace Ta doping in the bulk stabilizes the bulk structure and prevents mechanical cracks. This study highlights the importance of comprehensive modification of the bulk and surface for improving the electrochemical performance and provides a potential optimizing strategy for the commercialization of high-capacity Ni-rich cathode materials.

CuInS2/TiO2 heterojunction with elevated photo-electrochemical performance for cathodic protection

Semiconductor quantum dots with high quantum yield and photovoltaic conversion efficiency have ushered in a brilliant moment for constructing internal electric field heterojunctions for photogenerated cathodic protection applications. In this paper, TiO2 nanotubes grown vertically on the surface of titanium substrates were modified via a combination of conventional electrochemical oxidation and a one-step solvothermal pathway to sensitize with CuInS2 quantum dots. Compared with pure TiO2 photoelectrodes, the modification improves sunlight absorption efficiency and provides photoelectron cathodic protection to the 304 stainless steel (304 SS). Through 9 h solvothermal reaction, the CuInS2/TiO2 coupled with protected 304 SS exhibited an excellent property when the simulated sunlight irradiation. Its mixed open circuit potential is negatively shifted to -0.99 V, at the mean time with a stable photocurrent density (118 μA cm−2). The results indicate that CuInS2 and TiO2 established a p-n heterojunction with well-matched energy level, which can effectively facilitate the carrier separation and retain the strong redox capbility of photo-induced electrons and holes.

Iron (II) fluoride cathode material derived from MIL-88A

We report an eco-friendly, simple, and scalable method of FeF 2 cathode production. MIL-88A was synthesized in a water medium without any additives. It was used as a source of iron (3 +) ions during pyrolysis. The porous structure of such a sacrificial agent allowed us to incorporate poly-vinylidene fluoride molecules as a guest component into a host MIL-88A framework. Pyrolysis in Ar-flow results in two simultaneous processes: reducing Fe 3+ into Fe 2+ and forming porous carbon shells for FeF 2 nanoparticles. Applying complex analysis of high-resolution TEM images, porosity measurements, and XANES spectroscopy, we have revealed that obtained iron fluoride is composed of nanoparticles with elongated and hexagonal shapes. Both iron fluorides were attributed to tetragonal FeF 2 structure type, contained only Fe 2+ ions, and were covered with porous carbon shells. The obtained material was used as a cathode for a lithium-ion battery and showed good stability and a high capacity of 425–330 mA h/g. The proposed water-based synthesis of MIL-88A as a precursor in combination with mild pyrolysis conditions and good electrochemical performance make this material promising for cathode application. • We report the green and reproducible synthesis of MIL-88a. • For the first time, MIL-88a was applied as an iron and carbon source to produce FeF 2 . • MIL-88a was used as a host for polyvinylidene fluoride. • We obtained stable FeF 2 nanoparticles in a porous conductive carbon matrix. • This material was tested in a lithium-ion battery as a conversion cathode.

Bifunctional Electrocatalysts Materials for Non-Aqueous Li–Air Batteries

Rechargeable lithium–air batteries (LABs), particularly the nonaqueous form, are demonstrated as the next-generation energy conversion and storage equipment for many applications. The air cathode has been certified as one of the critical aspects to affect the full performance of the LABs. At present, the main challenge for the commercial application of air cathode is to exploit some new cathode catalysts with lower prices, higher efficiency, and better stability. In the last decade, tremendous efforts have been dedicated to developing new structure design and fabrication processes of the cathode materials to promote the full capability of the LABs. The recent research progress of bifunctional cathode catalysts for LABs, including the main improvement strategies and performance of cathode materials, is introduced in this paper. Besides, related technical challenges are analyzed, and possible resolving strategies for the challenges to develop the nonaqueous Li–air battery catalytic cathodes are elaborated on in this review.

Electrochemical and material characteristics of Ba0.5Sr0.5Co0.8Fe0.2O3−δ-Sm0.2Ce0.8O1.9 carbonate perovskite cathode composite for low-temperature solid oxide fuel cell

This paper presents the development of a new composite cathode Ba0.5Sr0.5Co0.8Fe0.2O3−δ-Sm0.2Ce0.8O1.9 carbonate (BSCF-SDCC). The BSCF-SDCC (50 wt% BDCF: 50 wt% SDCC) composite cathode was developed by low-speed ball milling in ethanol. The composite cathode is prepared in powder and pellet form, followed by calcination at 600 °C. The BSCF-SDCC composite cathode is examined by microstructural analysis, phase analysis, chemical bonding, thermal expansion coefficient (TEC), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy. X-ray diffraction proves the vigorous reaction between BSCF and SDCC powder after calcination. The carbonate bond in BSCF-SDCC was assessed by Fourier transform infrared spectroscopy (FTIR). TECs of the BSCF-SDCC cathode and SDCC matched each other. In TGA, BaCO3 weight gain is observed at 400 °C-650 °C for BSCF-SDCC powder without calcination. In general, BSCF-SDCC powder is not encouraged for calcination, but its pellet form is suitable. Electrochemical performance is tested from 400 °C to 600 °C. BSCF-SDCC after sintering achieves the lowest polarization resistance of 0.45 Ω, lowest area specific resistance of 0.29 Ωcm2, and highest conductivity of 149.0 Scm-1 at 600 °C. The conductivity is nearly 122% higher than BSCF, which only has a conductivity of 67 Scm-1. This is due to the existing carbonate layer which reduce the polarization loss and facilities the ions' conduction, thus electric conductivity is increased. The findings reveal a promising characteristic of the BSCF-SDCC composite for low-temperature solid oxide fuel cell cathode application.

Influence of practical operating temperature on the Cr poisoning for LSCF-GDC cathode

The influence of operating temperature on Cr poisoning effect on solid oxide fuel cells (SOFCs) cathode was comprehensive studied. The La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.90Gd0.10O1.95 (LSCF-GDC) symmetric cells were investigated at 550, 600, 650, 700, 750 °C respectively in the presence of Crofer 22 APU. After aging in the air for 200 h, the cell operated at 650 °C expressed the most serious degradation. At the operating temperature lower than 650 °C, the degradation rate was accelerated with the increased operating temperature. At the operating temperature higher than 650 °C, the degradation rate slowed down with the increased operating temperature. Combined the experimental results with first principles calculation, the mechanism could be put forward that competition existed between the oxygen reduction reaction (ORR) activity and the formation reaction of SrCrO4. The activity of ORR and the formation of SrCrO4 at different operating temperatures codetermined the fluctuating degradation rate of LSCF-GDC cathode. This result could offer a valuable guidance for the rational application of LSCF-GDC cathode in SOFCs.

Molecular engineering of sulfur‐providing materials for optimized sulfur conversion in Li‐S chemistry

AbstractThe practical implementation of lithium‐sulfur (Li‐S) batteries is greatly hampered by the low sulfur utilization and limited battery lifespan stemming from the complexity of the sulfur conversion reactions. As a core element in Li‐S chemistry, the intrinsic physiochemical properties of sulfur have predominant impacts on the final battery performance, and thus rational engineering of its structure at the molecular level may provide ample possibilities to optimize the sulfur conversion behaviors and hence to promote the commercialization of Li‐S technology. This review summarizes the recent advancements in tailoring the electrochemical performance of Li‐S batteries through engineering the molecular structures of sulfur‐providing materials themselves, such as by heteroatom doping, skeleton grafting, and construction of polysulfides‐based functional intermediates. Some new‐type inorganic sulfur‐equivalent active molecules with beneficial electrochemical properties for cathode application are also included. Finally, the perspectives on the challenges of molecular engineering of sulfur for achieving advanced Li‐S batteries are discussed.image

Industrial modification comparison of Ni-Rich cathode materials towards enhanced surface chemical stability against ambient air for advanced lithium-ion batteries

Ni-rich layered oxides (e.g. LiNi0.8Co0.1Mn0.1O2, denoted as NCM811) with high capacity and moderate cost are promising cathodes for high energy density Li-ion batteries. However, the highly chemical sensitivity to H2O and CO2 triggers the serious surface degradation when exposed to ambient air, which becomes an intractable obstacle for the large-scale production and application of Ni-rich cathodes. Herein, we comprehensively evaluate the effects of three industrial treatment strategies, including washing, washing–reheating, and washing–boron oxide coating–reheating, on the air stability, slurry processability and electrochemical performance of NCM811 cathodes. It is demonstrated that the slurry processability can be greatly improved by water washing. However, water washing leads to more inferior air stability, which can be restored via a post-heating treatment. Impressively, with the aid of B2O3 protective coating nanolayer, the thickening of surface degradation-induced passive layers is significantly suppressed that effectively prevents the detrimental surface phase transformation, thereby extending the ambient storage life and avoiding the slurry gelation. More importantly, B2O3 coated NCM811 cathode exhibits the low interfacial reaction resistance and excellent cyclic stability even after 8 weeks air exposure. This work paves the road for the industrial surface treatment of Ni-rich cathode materials, and deepens the understanding of surface stabilization mechanisms under practical application conditions.

Polarly modulated solvent strategy for high-voltage cathode materials

Sacrificial additive as an electrolyte engineering could regulate the electrode/electrolyte interface for advanced energy storage devices. In particular, the evolution of cathode electrolyte interface (CEI) is closely related with the epitaxial coordination environment of cathode materials. Herein, polarly modulated solvent strategy is successfully achieved, in which the electrochemical oxidation potential of perfluorinated electrolyte with tris(trimethylsilyl)borate additive is manipulated by the polarity of solvent structure. By taking Li-rich Mn-based oxide (LRM) as a model cathode, the interfacial quasicrystal bonding effects are ingeniously aroused between the interfacial lattice oxygen of LRM cathode and anchor oxygen CEI layer. More greatly, the formation energy of oxygen vacancy is effectively elevated by constructing the epitaxially strong covalent B/Si-O bonding, thereby considerably mitigating the lattice oxygen escaping and inhibiting the irreversible phase transformation. Consequently, LRM cathode with robust anchor oxygen CEI renders improved cycling stability after 200 loops with 87.5% capacity retention at 1C as compared to anchor oxygen-free LRM with only 61.9%. Given this, these findings inform new chemical and interface strategies to facilitate the application of high voltage cathodes.

The novel LiMn1.8Al0.2O4 nanosheets for high energy and power density supercapacitor cathode applications

The novel LiMn1.8Al0.2O4 nanosheets for high energy and power density supercapacitor cathode applications

Structural Regulation of Oxygen Vacancy-Rich K0.5 Mn2 O4 Cathode by Carbon Hybridization for Enhanced Zinc-Ion Energy Storage.

High-voltage manganese-based materials are considered as promising cathode materials for aqueous zinc-ion batteries (AZIBs). Herein, oxygen vacancy-rich K0.5 Mn2 O4 sheets were anchored uniformly onto honeycomb-like interconnected carbon nanoflakes (CNF@K0.5 Mn2 O4 ) for AZIB cathode applications. In the composite, the CNFs provided excellent intergranular electron transport capability, while the oxygen vacancies enhanced the electron transport efficiency inside crystals, and the embedded K ions expanded the interlayer spacing and stabilized the layered crystal structure. A reversible specific capacity of 241 mAh g-1 could be maintained by the composite at 0.5 A g-1 for 400 cycles. A combination of ex-situ analytical methods and density functional theory calculations was carried out to elucidate the electrochemical mechanism of reversible zinc storage. In addition, flexible quasi-solid-state batteries of Zn//CNF@K0.5 Mn2 O4 were constructed by substituting the traditional aqueous electrolyte for a quasi-solid-state gel electrolyte, which worked efficiently and exhibited high bending durability.

Increasing the performance of all-solid-state Li batteries by infiltration of Li-ion conducting polymer into LFP-LATP composite cathode

Polymer-ceramic composites combine the benefits of polymers and ceramics. In particular, the infiltration of the ceramic cathode with a Li-ion-conducting polymer in an all-solid-state Li battery enhances the utilization of the cathode active material (CAM) and enables the application of thicker cathodes with higher storage capacity. This concept has already been validated in our earlier work, in which a porous LiCoO2–Li6.45Al0.05La3Zr1.6Ta0.4O12 (LLZO:Al:Ta) composite cathode was fabricated by spark plasma sintering (SPS) technique. However, its performance stability was low. In the present work, the concept is modified using an LFP-LATP cathode with LiFePO4 as the CAM, Li1.5Al0.5Ti1.5(PO4)3 as the ion-conducting phase, and tape-casting with free sintering instead of SPS. Both tape-casting and free sintering are more relevant for large-scale production. The sintered LFP-LATP cathode is infiltrated with the MEEP polymer and LiC2NO4F6S2 ion-conducting salt. A full cell with the polymer-infiltrated cathode, LLZO:Al:Ta separator, and Li anode shows nearly full LFP utilization in the 100 μm thick cathode with an excellent area-specific storage capacity of above 3 mAh cm−2. However, after a few dozen cycles, a Li dendrite penetrates the separator leading to abrupt capacity fading. The prevention of Li dendrite formation remains a challenge for our future work.

Effective Nitrogen Incorporation for High‐Potential Anthracene Cathodes with Conjugated Frameworks

AbstractTo design high‐potential cathode materials for Li‐ion batteries through doping architecture, a well‐known anthracene framework is used as the basis for a broad array of nitrogen‐incorporated derivatives. A computational investigation of these derivatives clarifies that introduction of electron‐withdrawing nitrogen atoms improves the intrinsic redox potential at fully charged states, exhibiting a linear correlation between redox potential and electron affinity. However, this linear relationship between the redox potential and the density of nitrogen dopants is not fully followed during the discharging process. Consequently, it is found that doping one to three nitrogen atoms into anthracene is detrimental to the Li‐storage capacity, while doping four to ten nitrogen atoms is suggested as a suitable approach to improve the redox properties. At the end of the discharging process, electron affinity no longer plays a critical role in determining the redox potential. Each derivative is cathodically deactivated with the binding of the last Li atom, primarily owing to a sudden increase in the solvation energy, despite a negligible change in the electron affinity. These analyses assist to establish a promising approach for designing nitrogen‐incorporated anthracene derivatives for high‐performance cathode applications.