LiMn₂O₄ (LMO) has emerged as a promising electrode material for the electrochemical extraction of lithium from salt lakes due to its excellent lithium-ion selectivity and structural stability. However, the cyclic use of LMO in Salt Lake brines is often hindered by manganese dissolution and crystal structure collapse, primarily caused by the Jahn-Teller effect. These issues significantly reduce the cycling stability and lithium extraction efficiency of LMO, limiting its practical application. To address this challenge, we developed a molten salt-assisted gradient doping-coating synergistic modification technique aimed at effectively suppressing the Jahn-Teller effect. This approach facilitates the formation of chemically bonded MgO nanolayers on the LMO surface and incorporates Mg²⁺ into the bulk structure, thereby significantly enhancing the material's structural stability. Through a combination of density functional theory (DFT) calculations and experimental validation, the modified composite electrode exhibited superior kinetic performance, high capacity, and remarkable cycling stability. In simulated brine, it maintained a lithium adsorption capacity of 26.21 mg·g⁻¹ after 20 consecutive extraction cycles. Furthermore, in the West Taijinar old brine with a high Mg²⁺/Li⁺ ratio of 65.6, the modified electrode demonstrated a capacity retention rate of 81.8 %, approximately 34 % higher than pristine LMO, and reduced the Mg²⁺/Li⁺ ratio from 65.6 to 0.24. Furthermore, the modified electrode exhibited a manganese dissolution rate of only 0.34 %. These findings indicate that the proposed modification strategy significantly improves the cycling stability and lithium extraction performance of LMO, offering a viable pathway for its large-scale application in Salt Lake environments.

Cost-effective and efficient lithium extraction technology is vital to foster the growth of lithium industry. This paper proposed a novel approach for the high value utilization of spent LiFePO₄ (S-LiFePO₄) in the field of lithium extraction from salt lakes was proposed using spent LiFePO₄ (S-LiFePO₄) as raw material. The anode, made from spent LiFePO₄, is prepared via a sintering process, while FePO₄, obtained through chemical oxidation, is used as the cathode. Compared with commercial LiFePO₄, this system not only reduces the cost but also greatly shortens the preparation time of FePO₄ (only about 10min is required). And the electrochemical extraction system had a favorable lithium extraction capacity (29.25 mg/g) from actual brine, reducing the Mg/Li ratio from 61.4 to 0.8. This study not only achieved the low-cost preparation of electrode materials and facilitated the large-scale implementation of this process, but also proposed a high-value comprehensive utilization strategy for lithium-ion batteries recycling.

Constructing thick electrodes with high Li+ adsorption capacity and excellent kinetic performance effectively addresses the low efficiency of lithium extraction from salt lake brines. However, an increase in the content of active material can hinder the Li+ mass transfer within the electrode, resulting in polarization and reduced kinetic performance, which ultimately affects the extraction efficiency. This study synthesized a three-dimensional(3D) conductive network-incorporated thick electrode (∼20 mg/cm2) composed of the redox graphene oxide-loaded LFP(LFP/rGO) composite through an in situ hydrothermal method. The electrode material showed excellent kinetic performance and a high adsorption capacity for Li+ in salt lake brine. Under a constant voltage of 0.8 V in Li+ solution, the Li+ adsorption capacity reached 36.78 mg·g−1 within 10 min, exhibiting an average coulombic efficiency of over 83.53 %. Furthermore, the LFP/rGO composite thick electrode exhibited a Li+ adsorption capacity of 32.82 mg·g−1, along with an average coulombic efficiency of 74.6 %, even in the West Taijinar old brine solution. Additionally, the electrode material demonstrated remarkable cycling stability, maintaining a capacity of 172.09 mAh·g−1 after 50 cycles at a 0.2C rate in a high-concentration salt lake brine. Our preparation strategy offers novel insights for high-performance lithium extraction electrodes.

Improving the kinetic performance of thick electrodes is key to enhancing lithium extraction from salt lakes. Nano-melamine foam (MF), known for its unique porous structure, is ideal for building a three-dimensional (3D) conductive network, thereby boosting electrode kinetics. In our study, we developed a thick electrode (20 mg·g−1) with a 3D-conductive network by in-situ growing LiFePO4 (LFP) onto a nanoscale MF substrate. This electrode exhibited superior kinetic performance and a high lithium adsorption capacity in brine, achieving up to 32.8 mg·g−1 in just 10 min. Remarkably, even in simulated brine with a high Mg2+/Li+ ratio, it maintained an average coulomb efficiency of 62 %, significantly lowering the Mg2+/Li+ ratio from 65.6 to 0.47. It also showed exceptional stability in actual brine, maintaining an average coulomb efficiency of about 56.6 %. Our development of this high conductivity, thick electrode provides new insights into efficient lithium extraction methods.

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 LiFePO4 (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 settlement space along China’s Grand Canal is an important part of cultural heritage, boasting high value of conservation and inheritance as a museum of local culture in an active state. The paper is aimed at revealing the current situation and satisfaction with the settlement space environment along China’s Grand Canal Tianjin Section from the perspective of resident perception. We set up a structural equation model to perform an empirical analysis of the inherent relation of the components of the settlement space environment along China’s Grand Canal Tianjin Section and the inherent law influencing its current state. The research results show that the ecological factor of life along China’s Grand Canal exerted a positive influence on the ecological factor of production and the path coefficient was 0.344. The ecological factor of life and the factor of accessibility were in a relation of positive influence and the former had the most prominent influence on the latter, with a path coefficient of 0.534, while the path coefficient of the influence of the latter on the former was 0.131. The factor of social culture exerted a positive influence on the ecological factor of life, with the path coefficient being 0.765. The research conclusion analyzed the realistic difficulties of the settlement space environment along China’s Grand Canal, revealed the inherent law between different surveyed factors and provided basic reference for feature extraction, evaluation and optimized development of the settlement space along China’s Grand Canal.

The settlement space along China’s Grand Canal composes an important part of the Canal heritage, has a close bearing on the production and life of the residents there, nourishes rich culture and wisdom and boasts vital value of conservation and inheritance. Due to China’s rapid urbanization and industrialization, the settlements along the canal have been destroyed to some extent and their in-site characteristics urgently need excavation and conservation. Through field investigation, space syntax and GIS analysis, this paper performs quantitative analysis of the in-site characteristics of 18 typical rural settlements there. The findings show that: (1) The settlement space of industry dominant type for commerce and trade is comparatively dynamic and the capacity of topology and integration and the attractive force of the settlement center are stronger. (2) The dynamic scope of the citizens’ everyday traveling in the settlements has the closest correlation with the data of public-service facilities. (3) The settlements along the canal boast multiple, causal and blended in-site phenotype. The research findings provide new standards to categorize the settlements along China’s Grand Canal, paths and methods to explore the characteristics of the settlements and new cognitive perspectives to conserve and renew the settlements along China’s Grand Canal Tianjin Section.