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In this study, high-temperature solid-phase techniques are used to prepare pristine and Mg-modified LiNiO 2 cathode materials. Various characterizations are performed to analyze the morphology, structure, and electrical state of the two materials. Electrochemical tests show that Mg doping effectively improves the electrochemical properties of the materials. In particular, the modified sample exhibits a higher specific discharge capacity of 244.5 mA h g−1 than the pristine sample. Moreover, its maximum capacity retention after 304 cycles at 1 C is 54.1%. In situ X-ray powder diffraction imaging reveals that the modified material has better phase-transition reversibility than the pristine material. Density functional theory calculations indicate that Mg-doped Li sites can accelerate Li+ transport. Atomic force microscopy results demonstrate that Mg-doped Li sites act as supportive skeletons that enhance the mechanical properties of the material. Therefore, the proposed strategy for the Mg doping of Li sites can improve the architecture of LiNiO 2 cathode materials. [ABSTRACT FROM AUTHOR]

Configuring a carbon substrate with low surface polarity seems very important and significant for accelerating the cathode electrochemical performances of the Lithium-sulfur batteries, which is widely regarded as one of the most promising candidates for the next-generation green energy suppliers. The corn starch-derived carbon with in-situ multi-elements doping, initially carbonized by 6 mol/L H 2 SO 4 and then calcined in nitrogen atmosphere, is employed to configure sulfur cathode for Lithium–Sulfur batteries in this study. As-received carbon with randomly distributed graphical domains serves as charge carriers diffusion channels during discharging/charging cycles, thus endowing the cathode considerable excellent performances. Specifically, the loading amount of sulfur in cathode is around 60.31 wt% and the effective utilization efficiency of active reagent sulfur in cathode is up to 60 %. On activating the cathode at 0.114 A g−1 at 0, 25 and 40 °C, the initial discharge capacities of the Lithium–Sulfur batteries with corn starch-derived carbon-based composite cathode (with ∼1.3 mg cm−2 sulfur) are 278.6, 1023.7 and 976.1 mAh∙g−1, respectively. Accordingly, more uniform, and thinner solid electrolyte interphase membrane formed under room temperature activation, leaving in the dramatically diminished R sur value, contributes to the comparable cycling stability and rate performances of as-designed carbon-based sulfur cathode for Lithium–Sulfur Batteries. [ABSTRACT FROM AUTHOR]

Abstract In this study, we have successfully coated the CeO 2 nanoparticles (CeONPs) layer onto the surface of the Ni-rich layered LiNi 0.7 Co 0.2 Mn 0.1 O 2 cathode materials by a wet chemical method, which can effectively improve the structural stability of electrode. The X-ray powder diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) are used to determine the structure, morphology, elemental composition and electronic state of pristine and surface modified LiNi 0.7 Co 0.2 Mn 0.1 O 2. The electrochemical testing indicates that the 0.3 mol% CeO 2 -coated LiNi 0.7 Co 0.2 Mn 0.1 O 2 demonstrates excellent cycling capability and rate performance, the discharge specific capacity is 161.7 mA h g−1 with the capacity retention of 86.42% after 100 cycles at a current rate of 0.5 C, compared to 135.7 mA h g−1 and 70.64% for bare LiNi 0.7 Co 0.2 Mn 0.1 O 2 , respectively. Even at 5 C, the discharge specific capacity is still up to 137.1 mA h g−1 with the capacity retention of 69.0%, while the NCM only delivers 95.5 mA h g−1 with the capacity retention of 46.6%. The outstanding electrochemical performance is assigned to the excellent oxidation capacity of CeO 2 which can oxidize Ni2+ to Ni3+ and Mn3+ to Mn4+ with the result that suppress the occurrence of Li+/Ni2+ mixing and phase transmission. Furthermore, CeO 2 coating layer can protect the structure to avoid the occurrence of side reaction. The CeO 2 -coated composite with enhanced structural stability, cycling capability and rate performance is a promising cathode material candidate for lithium-ion battery. [ABSTRACT FROM AUTHOR]

This study synthesizes pristine and Nb-doped lithium-rich manganese-based cathode materials by solvothermal and high-temperature solid-phase methods. Analysis by focused ion beam scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy indicates successful Nb doping into the material's bulk structure. Electrochemical evaluation reveals that electrochemical performance is significantly enhanced by Nb doping. The discharge capacity of Nb-0.02 can maintain 271.7 mAh·g−1, and its cycle retention rate is up to 98.50% after 300 cycles at 0.2C; however, under the same parameters, the pristine material's discharge capacity and cycle retention rate are 212.8 mAh·g−1 and 86.68%. The initial coulombic efficiency and initial discharge capacity of Nb-0.02 is 86.94% and 287.5 mAh·g−1, while that of the pristine material is 73.59% and 234.2 mAh·g−1. Density functional theory calculations demonstrate that Nb doping accelerates Li-ion diffusion and stabilizes material structure due to stronger Nb–O bonds from reduced Li-ion migration barrier energy. Thus, the proposed modification strategy for Nb doping can illuminate the structural design of lithium-rich manganese-based cathode materials. • Nb elements are distributed across the surface and in the bulk material. • ICE and cycle performance are significantly enhanced by Nb doping. • DFT calculations confirm that Nb doping accelerates Li-ion diffusion. [ABSTRACT FROM AUTHOR]

Enhancing the kinetic performance of thick electrodes is essential for improving the efficiency of lithium extraction processes. Biochar, known for its affordability and unique three-dimensional (3D) structure, is utilized across various applications. In this study, we developed a biochar-based, 3D-conductive network thick electrode (∼20 mg cm−2) by in-situ deposition of LiFePO 4 (LFP) onto watermelon peel biomass (WB). Utilizing Density Functional Theory (DFT) calculations complemented by experimental data, we confirmed that this The thick electrode exhibits outstanding kinetic properties and a high capacity for lithium intercalation in brines, even in environments where the Magnesia-lithium ratios are significantly high. The electrode showed an impressive intercalation capacity of 30.67 mg g−1 within 10 min in a pure lithium solution. It also maintained high intercalation performance (31.17 mg g−1) in simulated brines with high Magnesia-lithium ratios. Moreover, in actual brine, it demonstrated a significant extraction capacity (23.87 mg g−1), effectively lowering the Magnesia-lithium ratio from 65 to 0.50. This breakthrough in high-conductivity thick electrode design offers new perspectives for lithium extraction technologies. The watermelon peel serves as the substrate, simultaneously supporting the in-situ loading of LFP, thereby forming an LFP/WB thick electrode exhibits high lithium absorption capacity and excellent kinetic performance in high Mg2+/Li+ ratio brine. It achieved an impressive absorption rate of 30.67 mg g−1·min−1 in 10 min and an average lithium extraction of 23.87 mg g−1 from salt lake brine. This approach effectively reduced the Mg2+/Li+ ratio from 65 to 0.50, enabling efficient lithium separation and comprehensive biological resource utilization. [Display omitted] • The comprehensive utilization of biological resources is achieved. • The low efficiency of Li + extraction with thick electrode is effectively solved. • Effectively reducing the Mg2+/Li+ ratio in low-grade brine. [ABSTRACT FROM AUTHOR]

Layered high-nickel LiNi 0.8 Co 0.1 Mn 0.1 O 2 is a promising candidate of the next generation cathode materials for lithium-ion batteries. However, severe cycling instability and fast capacity drop induced by anisotropic structured change restrict its wide application. To address these defects, the structure design of cathodes is conducted. Herein, a hierarchical layered LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode consisting of orderly stacking hexagonal nanosheets with exposed active {104} facets is successfully synthesized by an improved co-precipitation process and followed with a high temperature lithiation reaction. Benefiting from this unique texture, exposed active {104} facets with lower surface energy supply 3D barrier-free Li+ ion diffusion channels, significantly improving the efficiency of the Li+ diffusion. Moreover, the consistent arrangement of nanosheets in the manner of the {001} facets close attachment is beneficial to alleviate the stress caused by the anisotropic structured change. Thus, this cathode material presents both superior reversible capability (203.8 mAh g−1 at 0.1C, 184.5 mAh g−1 at 1 C, 173.0 mAh g−1 at 5 C and 161.3 mAh g−1 at 10 C) and stable cycling performance (capacity retention of 89.3% after 100 cycles at 1 C, 55.3% after 300 cycles at 5 C and 59.6% after 300 cycles at 10 C). Schematic of single crystal shape evolution of the cathode materials and the corresponding cycle performance of the NCM-3 sample at different rates. [Display omitted] • A hierarchical cathode material consisting of orderly stacking nanosheets with exposed active {104} facets was successfully synthesized. • The exposed active {104} facets with lower surface energy could supply barrier-free Li+ ion diffusion channels. • The consistent arrangement of nanosheets is beneficial to alleviate the stress and inhibit the pulverization of secondary particles. • The hierarchical cathode material presents both superior reversible capability and stable cycling performance. [ABSTRACT FROM AUTHOR]

Lithium-rich manganese-based oxides are included in high-capacity cathodes. Herein we introduce a certain amount of Mg and Na into lithium-rich manganese-based oxide microspheres to overcome the weak cycling performance and poor rate capacity. This work uses the hydrothermal method combined with the high-temperature solid-phase method and CH 3 COONa and C 4 H 14 MgO 8 as dopants. Transmission electron microscopy (TEM), X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical characterization are performed to systematically assess the effect of Na and Mg element doping on the morphology, structure and electrochemical characteristics of Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2. The results show that the material has excellent electrochemical performance. These improvements could be related to the presence of Na in Li layers and Mg in TM layers, which can speed up Li-ion diffusion kinetics and improve ionic and electronic conductivity. DFT calculations demonstrate that the injection of Na and Mg reduces the lithium-ion migration barrier energy. This dual-doped modification technique may help researchers better understand how to build high-capacity and stable cathode materials for LIBs. [ABSTRACT FROM AUTHOR]

• Commercial multi-walled carbon nanotubes (MWCNTs) were activated under ultrasonic treatment with nitric acid in one step. • The usage of only 700 ppm activated MWCNTs catalyst increases MEA-based CO 2 desorption amount by 48.49 % and desorption rate by as high as 338.50 %. • The activated MWCNTs catalyst and MEA solution show outstanding stabilities within 20 cyclic CO 2 sorption and desorption tests. Organic amine solution is currently the most commonly used chemical absorbent for carbon dioxide (CO 2) capture, but its drawback such as high energy consumption for regeneration of CO 2 loaded solution has seriously hindered its wide application in industry. Development of catalysts could reduce the regeneration energy consumption of the process. In this study, the catalytic effects of raw multi-walled carbon nanotubes (MWCNTs) and acid-treated MWCNTs in 30 wt% monoethanolamine solution on both absorption and desorption procedures were investigated. The results showed that the addition of raw MWCNTs and acid-treated MWCNTs as catalysts both promoted the CO 2 desorption rate and amount, among which the 700 ppm acid-treated MWCNTs increased the CO 2 desorption amount by 48.49 %. Furthermore, both MWCNTs shortened the desorption time of CO 2 as well. Stability of acid-treated MWCNTs has been examined by 20 cycles in the capture system. Characterization results indicate that the acid treatment increased the surface area of MWCNTs, and created more acid sites on their surfaces through the defected area. Both characteristics contribute to the enhanced CO 2 desorption performance. Therefore, acid-treated MWCNTs can be considered as promising catalysts for promoting CO 2 desorption and reducing energy consumption for CO 2 capture. [ABSTRACT FROM AUTHOR]

Carbon spheres, prepared by hydrothermally treating fresh potato starch, is employed as the sulfur host to configure a high-performance cathode substrate candidate for Li–S batteries. As confirmed by experimental results, both the improved the rate and cycle performances of Li–S batteries cathode with gradient sulfur immobilization, are mainly attributed to the confining, adsorption and conduction multi-functions of as-prepared carbon spheres toward polysulfides. Specifically, on starting the discharging/charging cycles, the active material α-S 8 is irreversibly converted to polysulfides and then transformed between β-S 8 and polysulfides during the next charge/discharge cycles. After initialization at 0.1C for 3 cycles, the initial reversible discharge capacities of the Li–S batteries cathode with optimized sulfur amount are 1072.5, 831.3, 780.4, 726.8, 714.3, 702.7 mAh g−1 sulfur at 0.1, 0.5, 1, 2, 3 and 4 C, which is superior to those of the most previously reported reports. Besides that, as-designed potato-derived carbon based composite cathodes exhibits remarkable rate performance and cycling stability even at wide temperature ranging from −40 to 60 °C, which evidently supports the dominant role of as-prepared 3D carbon spheres in boosting the cathode performance for Li–S batteries. [ABSTRACT FROM AUTHOR]