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Oxygen loss is a serious problem of lithium‐rich layered oxide (LLO) cathodes, as the high capacity of LLO relies on reversible oxygen redox. Oxygen release can occur at the surface leading to the formation of spinel or rock salt structures. Also, the lattice oxygen will usually become unstable after long cycling, which remains a major roadblock in the application of LLO. Here, it is shown that Zr doping is an effective strategy to retain lattice oxygen in LLO due to the high affinity between Zr and O. A simple sol‐gel method is used to dope Zr4+ into the LLOs to adjust the local electronic structure and inhibit the diffusion of oxygen anions to the surface during cycling. Compared with untreated LLOs, LLO–Zr cathodes exhibit a higher cycling stability, with 94% capacity retention after 100 cycles at 0.4 C, up to 223 mAh g−1 at 1 C, and 88% capacity retention after 300 cycles. Theoretical calculations show that due to the strong Zr–O covalent bonding, the formation energy of oxygen vacancies has effectively increased and the loss of lattice oxygen under high voltage can be suppressed. This study provides a simple method for developing high‐capacity and cyclability Li‐rich cathode materials for lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

The degradation of Li‐ and Mn‐rich (LMR) cathodes primarily results from the thermodynamic instability of lattice oxygen and the resulting oxygen release. This is promoted by localized lattice strain, which develops dynamically during electrochemical reactions involving repeated Li‐ion intercalation and extraction. However, the role of chemomechanical strain in degrading lattice oxygen's stability is not yet well‐understood. Here, the research indicates that uneven strain distribution causes bending, resulting in lower activation energy for oxygen vacancy creation and injection into particle interiors at bending points. Combining in situ transmission electron microscopy and theoretical simulations, it is shown that the largest O─O interaction occurs at the maximum curvature point, reducing Mn─O bonding strength, promoting oxygen dimer formation, and eventually initiating oxygen release from LMR. As a result, a process is designed to adjust the Li‐content and the distribution of the two‐phase structure, achieving better cycling stability in LMR cathodes with a more balanced distribution of strain. These results provide insights into enhancing LMR cycling stability while utilizing their high capacity. [ABSTRACT FROM AUTHOR]

Traditional approaches for monitoring human gait have severe spatial and temporal restrictions with complex analysis methods and high cost, which are powerless to promote the development of intelligent life involving fitness, sport training, and healthcare. Herein, a portable smart insole system with high spatial resolution and simple manufacturing process to measure plantar pressure distribution anytime, anywhere for gait analysis is proposed. An insole‐shaped array of 104 piezoresistive sensors with highly robust characteristics is assembled, exhibiting a good pressure‐sensing uniformity. The smart insole not only detects the subtle displacement of the center of gravity of the body, but also exhibits a real‐time, high‐resolution thermodynamic diagram of the plantar pressure distribution during human activities. More importantly, the function of motion intelligence identification can be realized by regionalizing and digitizing the whole plantar pressure distribution, achieving an average recognition accuracy of 83.32% among six predefined motions. These results imply that the carbon fiber‐based smart insole can provide an effective approach for convenient gait analysis and motion identification, which has a great potential in the application of future intelligent life. [ABSTRACT FROM AUTHOR]

Tunnel projects in the southwestern mountainous area of China are in full swing. According to the tunnel burial depth, structural characteristics, and chemical erosion environments of the Lixiang railway tunnel, carbonaceous slate specimens obtained in the field were taken to experimentally investigate the physical, mechanical, and creep characteristics of the bedding's slate specimens after chemical erosion. The results of scanning electron microscopy (SEM) indicate that chemical erosion leads to internal damage in the carbonaceous slate specimens, and the internal damages are increasing with the increase of erosion days. Moreover, the specimens' ultrasonic test (UT) results prove that specimens with smaller bedding angles suffer a more serious erosion and induce more internal cracks. Under conventional triaxial compression conditions with 40 MPa of confining pressures, the conventional triaxial compressive strength (σs) decreases with the decrease of the bedding angle and the increase of erosion days, and the failure modes of the specimens are mainly controlled by oblique shear fractures and accompanied by the occurrence of slip dislocation fractures between the bedding inclination. Under creep conditions with 40 MPa of confining pressures, the final deformations of specimens are increasing with the increase of erosion days, which means the longer the erosion days, the greater the deformations. The failure modes of the specimens under creep conditions are controlled by shear fractures, and for the specimen with a 60° bedding angle and long-term erosion, there are block separations and many cavities along the shear planes. Therefore, more attention should be paid to prevent serious failure of the surrounding rock if the surrounding rock has a bedding angle of 60° or suffers long-term erosion. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) are currently widely applied in many aspects of life, but with the development, the capacity of lithium‐ion batteries can no longer meet the needs. One of the dominant factors to restricting the capacity of LIBs is the cathode materials. Among the derivatives of spinel cathode LiMn2O4 (LMO), LiNi0.5Mn1.5O4 (LNMO) has become one of the research promising cathode materials in the current LIBs due to its high working voltage (4.7 V) and large theoretical specific capacity (147 mAh g−1). However, the short cycle life of LNMO during the electrochemical process limits its large‐scale commercial applications. Thus, it is necessary to summarize and discuss the recent development of LNMO. Through comparison with LiMn2O4, the structure, electrochemical properties of LNMO, influence of Mn on the performance of LNMO, and the capacity fading mechanism are analyzed and discussed in detail. We also summarize the modification methods of LNMO and the influence of preparation methods on the structure and performance of LNMO. Finally, some prospects of LNMO cathode are put forward. This Review article can provide helpful references for future design and construction of LNMO. [ABSTRACT FROM AUTHOR]

Theoretically, carbonaceous materials with a high degree of graphitization and large surface area are beneficial for Li+ storage, and those with a large surface area and enlarged interlayer spacing are beneficial for Na+ storage. However, synchronously realizing them in carbonaceous materials at moderate temperatures is still a huge challenge. Herein, using bifunctional silica (SiO2), as a catalyst for graphitization of carbon and template for pore-forming, we propose a strategy to enhance the graphitization and surface area of carbonaceous materials simultaneously, besides N, P co-doping. As an anode material, the obtained 3D porous carbon network shows ideal cycling stability and excellent rate capability for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs): outstanding reversible capacities of 1038 mA h g−1 and 238 mA h g−1 are delivered separately for LIBs and SIBs at a current of 1 A g−1. Also, it demonstrates a good rate capability at a higher current of 10 A g−1 and excellent cycling stability at 5 A g−1 for 2000 cycles for LIBs and SIBs. These results illuminate the design principle of carbonaceous materials for Li and Na storage by considering the high degree of graphitization, large specific surface area and heteroatom doping, endowing LIBs and SIBs with promising performance and applications. [ABSTRACT FROM AUTHOR]

Poisson's ratios of two-dimensional (2D) all-inorganic perovskites Cs2PbX4 (X = Cl, Br, I) have been calculated by the first-principles calculations. The contribution of each geometric parameter (bond length L , bond angle Φ , rotation angle 𝜃 1 , and tilt angle 𝜃 2 ) to Poisson's ratio is obtained analytically. Through a comprehensive analysis of the geometric deformations of the perovskite under the uniaxial strain, we find that Poisson's ratios of the perovskites are sensitive to the change of the bond length L and the bond angle Φ. In addition, the value of the bond angle Φ 0 in the strain-free structure mainly determines the high in-plane anisotropy of Poisson's ratios in Cs2PbX4. [ABSTRACT FROM AUTHOR]

Li-CO 2 batteries arouse great interest in the context of carbon neutralization, but their practicability is severely hindered by the sluggish CO 2 redox reaction kinetics at the cathode, which brings about formidable challenges such as high overpotential and low Coulombic efficiency. For the complex multi-electron transfer process, the design of catalysts at the molecular or atomic level and the understanding of the relationship between electron state and performance are essential for the CO 2 redox. However, little attention is paid to it. In this work, using Co 3 S 4 as a model system, density functional theory (DFT) calculations reveal that the adjusted d-band and p-band centers of Co 3 S 4 with the introduction of Cu and sulfur vacancies are hybridized between CO 2 and Li species, respectively, which is conducive to the adsorption of reactants and the decomposition of Li 2 CO 3 , and the experimental results further verify the effectiveness of energy band engineering. As a result, a highly efficient bidirectional catalyst is produced and shows an ultra-small voltage gap of 0.73 V and marvelous Coulombic efficiency of 92.6%, surpassing those of previous catalysts under similar conditions. This work presents an effective catalyst design and affords new insight into the high-performance cathode catalyst materials for Li-CO 2 batteries., (© 2023 Wiley-VCH GmbH.)

Water electrolysis is an ideal method for industrial green hydrogen production. However, due to increasing scarcity of freshwater, it is inevitable to develop advanced catalysts for electrolyzing seawater especially at large current density. This work reports a unique Ru nanocrystal coupled amorphous-crystal Ni(Fe)P 2 nanosheet bifunctional catalyst (Ru-Ni(Fe)P 2 /NF), caused by partial substitution of Fe to Ni atoms in Ni(Fe)P 2 , and explores its electrocatalytic mechanism by density functional theory (DFT) calculations. Owing to high electrical conductivity of crystalline phases, unsaturated coordination of amorphous phases, and couple of Ru species, Ru-Ni(Fe)P 2 /NF only requires overpotentials of 375/295 and 520/361 mV to drive a large current density of 1 A cm -2 for oxygen/hydrogen evolution reaction (OER/HER) in alkaline water/seawater, respectively, significantly outperforming commercial Pt/C/NF and RuO 2 /NF catalysts. In addition, it maintains stable performance at large current density of 1 A cm -2 and 600 mA cm -2 for 50 h in alkaline water and seawater, respectively. This work provides a new way for design of catalysts toward industrial-level seawater splitting., (© 2023 Wiley-VCH GmbH.)

Due to the higher energy density, high thermal stability, and low cost, LiNi 0.5 Mn 1.5 O 4 (LNMO) spinel, with a large voltage operating window, has been one of the most promising cathode materials for lithium-ion batteries (LIBs). However, the interfacial reaction between the cathode and electrolyte and the two-phase reaction within the bulk of LNMO would destroy the original structure and lead to capacity deterioration, posing a significant challenge. Therefore, the way to suppress the transition-metal (TM) dissolution in LNMO has attracted much attention. However, the ordered/disordered phase regulation by metal atom doping to prohibit TM dissolution has not been extensively explored. Herein, a Ge-doping strategy is proposed to adjust the ratio of disordered/ordered phases in LNMO, resulting in exceptional structural stability. For the modified spinel cathode, there is almost no voltage drop and the capacity retention is up to 92.2% over 1000 cycles at 1C. These results demonstrate that incorporating Ge into LNMO forms a robust structure that effectively increases the amount of Mn 4+ while blocking the diffusion of TM ions. In addition, Ge-doping also protects the bulk from further reactions with electrolytes, significantly enhancing the interfacial stability and relieving voltage decay in cycling. This approach can also be applied to design other high-stability cathodes through ordered/disordered phase regulation.