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The α-Ni(OH)2 coated with manganese (Mn) materials was synthesized by the chemical precipitation method, and the electrochemical properties were investigated. The results showed that the ingredient of the coating is a mixture of MnO2 and Mn2O3, and the coating can inhibit the intercalated anions escape and stabilize the α-Ni(OH)2 phase structure in KOH alkaline solution. The coated electrodes have higher discharge capacities and higher capacity retention rates than the uncoated α-Ni(OH)2 electrode, the discharge capacity of Mn-coated electrodes is over 350 mAh g−1, and the capacity retention rate exceeds 92%, separately. The reason may be that the Mn coatings can block or decelerate water molecule and the anion to escape from the interlayers, therefore prevent α phase structural collapse and maintain high discharge capacity during a long lifespan cycle. Therefore, the Mn coating α-Ni(OH)2 is a promising candidate for high-power Ni-MH batteries.

Reducing cobalt dependency has attracted great interest for lithium batteries manufacturing due to limited cobalt resources and high prices. A highly promising LiNi0.6Co0.05Mn0.35O2 (NCM60535) high-nickel low cobalt lithium layered oxide cathode material is successfully prepared by systematically examining the two key synthesis conditions of pH and annealing temperature. The obtained materials exhibit a uniform size distribution, good spherical morphology, clear structure, and homogeneous element distribution. NCM60535 shows competitive electrochemical properties: when compared with the LiNi1/3Co1/3Mn1/3O2, with a higher output specific capacity and cycling stability at 4.3 V low voltage; when compared with the LiNi0.8Co0.1Mn0.1O2, with a comparable discharge capacity but relatively poor cycling stability at 4.5 V high voltage. A new type of electrolyte that combines high lithium salt concentration, EC-free solvent system, and VC and LiPO2F2 functional additives is designed and greatly improves the electrochemical properties of the material under high voltage. Moreover, it also delivers superior electrochemical properties in high voltage lithium full battery (270 Wh Kg−1). And we suggest that NCM60535 is expected to become a substitute for the currently widely commercialized LiNi1/3Co1/3Mn1/3O2 (NCM333), LiNi0.5Co0.2Mn0.3O2 (NCM523), LiNi0.6Co0.2Mn0.2O2 (NCM622), and LiNi0.8Co0.1Mn0.1O2 (NCM811) due to its relatively low production cost and competitive electrochemical properties.

Metal-organic framework (MOF)-derived materials are attracting considerable attention because of the moldability in compositions and structures, enabling greater performances in diverse applications. However, the nanostructural control of multicomponent MOF-based complexes remains challenging due to the complexity of reaction mechanisms. Herein, we present a surface-induced self-nucleation-growth mechanism for the zeolitic imidazolate framework (ZIF) to prepare a new type of ZIF-8@SiO2 polyhedral nanoparticles. We discover that the Zn hydroxide moieties (Zn-OH) within ZIF-8 can trigger the hydrolysis of tetraethyl orthosilicate effectively on the ZIF-8 surface precisely, avoiding the formation of free orthosilicic acid (Si(OH)4) successfully. This is a pioneering work to elucidate the importance of MOF surface properties for preparing multicomponent materials. Then, a novel well-dispersed silicon hollow nanocage (H-Si@C) modified by the carbon was prepared after removal of the ZIF-8 and magnesiothermic reduction. The as-prepared H-Si@C demonstrates an overwhelmingly high lithium storage capability and extraordinary stability in lithium-ion batteries (LIBs), particularly the impressive performances when it was matched with the LiNi0.6Co0.2Mn0.2O2 cathode in a full cell. The MOF surface-induced self-nucleation-growth strategy is useful for preparing more multifunctional materials, while the study of lithium storage performances of the H-Si@C material is practical for LIB applications.

Modification using carbon nanotubes (CNTs) is one of the most important strategies to boost the performance of materials in various applications, among which the CNT-modified silicon-based anodes have gained considerable attention in lithium-ion batteries (LIBs) due to their improved conductivity and cycle stability. However, the realization of a close-knit CNT coating on silicon (Si) through an efficient and cost-effective approach remains challenging. Herein, a new in situ self-catalytic method by acetylene treatment is presented, in which, CNTs can be directly grown and knitted on the SiOx particles to construct a conductive additive-free SiOx@CNT anode. The in situ grown CNTs can not only enhance electric conductivity and alleviate the volume effect of SiOx effectively, but also mitigate the electrolyte decomposition with improved coulombic efficiency. As a result, an extremely high capacity of 1012 mA h g−1, long lifespan over 500 cycles at a current density of 2 A g−1 as well as a good performance in full LIBs with a working potential of about 3.4 V (vs. nickel-rich cathode) were obtained. The rationally constructed SiOx@CNTs with easy synthesis and high throughput will hopefully promote LIBs with energy density above 300 W h kg−1. This study opens a new avenue to prepare CNT-decorated functional materials and brings the SiOx-based anode one step closer to practical applications.

High-voltage high-nickel low-cobalt lithium layered oxide cathodes show great application prospects for lithium-ion batteries due to their low cost and high capacity. However, deterioration of the bulk structure and the electrode-electrolyte interface will significantly endanger the cycle life and thermal stability of the battery as the nickel content and voltage increase. We present here a lattice doping strategy to greatly improve the cell performance by doping a small dose of Ti (2 mol %) in LiNi0.6Co0.05Mn0.35O2. Through density functional theory calculations, we know that the diffusion energy barrier of Li+ decreases and the activation energy of surface lattice oxygen atom loss increases after Ti doping, thereby improving the rate performance and inhibiting the undesired phase transition. The battery in situ X-ray diffraction (XRD) pattern demonstrates that Ti doping tunes the H1-H2 phase-transition process from a two-phase reaction to a single-phase reaction and inhibits the undesired H2-H3 phase transition, minimizing the mechanical degradation. The variable temperature in situ XRD reveals delayed phase-transition temperature to improve thermal stability. These improvements can be attributed to Ti doping to passivate the reactivity of the layered oxide cathode, which is fundamentally related to the strong Ti-O bond and no unpaired electrons for Ti4+. This work provides valuable strategic guidelines for the use of high-voltage high-nickel low-cobalt cathodes in lithium-ion batteries.

New hierarchical hollow SiO2 spheres (HHSs) decorated with metal nanoparticles (i.e., Co, Co–HHS) were designed using an in situ self-assembly approach. The Co nanoparticles were found to have a catalytic effect on (de-)lithiation of SiO2 and hence in storing lithium. Then, an extremely high capacity of 932 mA h g−1 and good cycling stability for more than 1000 cycles were demonstrated in the corresponding lithium battery. In addition, the lithium-ion full batteries of the Co–HHS versus lithium layered oxide cathode (e.g., LiNi1/3Co1/3Mn1/3O2, NCM333) were introduced and showed good performance, demonstrating the promising application of the Co–HHS, in particular for pursuing high-energy-density batteries.

Silica is a very promising anode material for lithium-ion batteries, due to its advantages of being resource-rich and having high theoretical specific capacity. However, poor electrochemical activity severely limits its practical application. To solve this issue, a nanosheet-assembled silica hierarchical hollow sphere decorated with ultrafine cobalt nanoparticles and carbon (SiO2/Co/C) is successfully synthesized. The hollow structure can effectively alleviate the volume expansion, shorten the migration distance of lithium ions, and increase the binding site. Furthermore, the carbon matrix and highly active ultrafine cobalt nanoparticles enhance not only the electronic conductivity but also the electrochemical activity (catalyzing the breaking of Si–O and Li–O bonds) of SiO2. The resulting SiO2/Co/C composite has a high reversible capacity of 1160 mA h g−1 at 0.2 A g−1 and still has a specific capacity of 548 mA h g−1 after 1000 cycles at a high current density of 1.0 A g−1. Moreover, the SiO2/Co/C composite also exhibits good electrochemical performance in a full cell.

Modification using carbon nanotubes (CNTs) is one of the most important strategies to boost the performance of materials in various applications, among which the CNT-modified silicon-based anodes have gained considerable attention in lithium-ion batteries (LIBs) due to their improved conductivity and cycle stability. However, the realization of a close-knit CNT coating on silicon (Si) through an efficient and cost-effective approach remains challenging. Herein, a new in situ self-catalytic method by acetylene treatment is presented, in which, CNTs can be directly grown and knitted on the SiO

While Sb-based materials are attracting much attention as promising lithium/sodium ion batteries anodes because of excellent theoretical specific capacity (660 mAh g−1), it is still challenging to achieve long cycling stability and excellent rate capability due to sluggish reaction kinetics and serious volume expansion during electrochemical process. Herein, to alleviate this issue, we design a novel nitrogen-enriched Sb@NCs composite through a facile and simple organic-inorganic coordination reaction, which could ensure metal ions and nitrogen element distributed on the carbon framework uniformly. In the lithium/sodium ion batteries matched with Sb@NCs composites with high nitrogen content (9.81 at.%) exhibit outstanding performances that a high-rate performance of 263.9 mAh g−1 at 25 A g−1 for lithium ion storage and a discharge capacity of 359.8 mAh g−1 at 0.1 A g−1 after 250 cycles for sodium ion storage. This facile and novel method may pave a way to prepare nitrogen-enriched materials to improve the ion storage and rate performances.

Rechargeable lithium-ion batteries (LIBs) dominate the energy market, from electronic devices to electric vehicles, but pursuing greater energy density remains challenging owing to the limited electrode capacity. Although increasing the cut-off voltage of LIBs (>4.4 V vs. Li/Li+ ) can enhance the energy density, the aggravated electrolyte decomposition always leads to a severe capacity fading and/or expiry of the battery. Herein, a new durable electrolyte is reported for high-voltage LIBs. The designed electrolyte is composed of mixed linear alkyl carbonate solvent with certain cyclic carbonate additives, in which use of the ethylene carbonate (EC) co-solvent was successfully avoided to suppress the electrolyte decomposition. As a result, an extremely high cycling stability, rate capability, and high-temperature storage performance were demonstrated in the case of a graphite|LiNi0.6 Co0.2 Mn0.2 O2 (NCM622) battery at 4.45 V when this electrolyte was used. The good compatibility of the electrolyte with the graphite anode and the mitigated structural degradation of the NCM622 cathode are responsible for the high performance at high potentials above 4.4 V. This work presents a promising application of high-voltage electrolytes for pursuing high energy LIBs and provides a straightforward guide to study the electrodes/electrolyte interface for higher stability.

The ammonia-low hydroxide coprecipitation process has successfully synthesized Ni0.6Co0.2Mn0.2(OH)2 precursor by replacing ammonia with NH4+ and lowering the pH of the salt solution with acid. NH4+ and H+ increase the diffusion range of the salt solution and both react with OH−, which would reduce the nucleation rate and increase the complexation under low ammonia concentration conditions. The optimal pH of coprecipitation is determined from the theoretical calculation on the competitive relationship between complexation (Me(NH3)n2+) and precipitation (OH−) using chemical equilibrium and solubility product constant. And compared with other different complexing agents (e.g., NH4+, H+, and NH3), the material obtained with both NH4+ and H+ has the optimized particle morphology, size, composition, and element distribution. The resulting LiNi0.6Co0.2Mn0.2O2 cathode material exhibits superior electrochemical properties, when compared to a commercial sample, with a high initial discharge capacity (176.6 mAh g−1), cycling stability (91.9% retention for 100 cycles), and rate capability (115.7 mAh g−1 at 3C). Moreover, it also demonstrates excellent electrochemical performance in lithium-ion full batteries matched with commercial graphite or Si/C anodes. Ammonia-low coprecipitation synthesis would greatly reduce the treatment cost of production wastewater, improve the working environment of operators, and protect the natural ecological environment of the earth.

To analyze the influence of different soil properties on pile foundation load-bearing characteris- tics, taking a section of railway in Xi'an and a bridge of Xi'an as test area, and by field static load test to study load transfer characteristics after the test piles under axial pressure, including the distribution of axial force, pile lateral friction, tip resistance traits, ultimate bearing capacity determine, and compare with the theory bearing capacity. Experimental results show that, adjacent soil properties change large, axial force and lateral friction mutation at the junction of corresponding soil layer. Silty clay in different parts is below ground, and its lateral friction plays much difference. Pile lateral friction plays an important role in bearing capacity, but the role of round gravel soil end bearing capacity to pile bearing capacity can't be ignored. Tests calculate pile bearing ca- pacity significantly larger than standardized formula calculation bearing capacity, which are respectively 55.35% and 119.1%. And give the similar project condition the suggested values of pile bearing capacity and soil friction, to provide reference for similar pile foundation design.