Battery-grade lithium hydroxide monohydrate (LiOH·H₂O) is critical for lithium-ion batteries, yet its conventional causticization production faces sustainability challenges regarding waste management. This work systematically investigated the leaching kinetics and controlling mechanisms of lithium (Li) from lithium carbonate (Li₂CO₃) during causticization. The leaching behavior was found to follow the Avrami diffusion-controlled model, exhibiting a fast initial reaction rate with an apparent activation energy of 7.35 kJ·mol^-1. The leaching of Li was limited by the heterogeneous nucleation of calcium carbonate (CaCO₃) on Li₂CO₃ particles. An optimized strategy (CP-R) was proposed in this study, which involves calcining CaCO₃ precipitate to recover quicklime with a purity of 96.29%, and utilizing the Li₂CO₃ covered by the dense layer in the precipitate as additive for causticization, thereby achieving a closed-loop cycle of Li and Ca. Comprehensive economic analysis and life cycle assessment demonstrate that CP-R offers higher profitability and lower environmental impact compared to conventional causticization and electrodialysis bipolar membrane process. Overall, CP-R presents a compelling alternative for LiOH production by simultaneously addressing solid waste disposal and enabling closed-loop Li recycling.

Wearable electronics require compact, reliable, and sustainable power sources. Fabric-based triboelectric nanogenerators (TENGs) offer a promising solution by combining energy harvesting with the inherent softness and breathability of textiles. However, conventional functionalization methods, such as surface coatings or multilayer structures, inevitably diminish these essential properties. To address this issue, we developed a knitted fabric-based direct current triboelectric nanogenerator (KF DC-TENG) using whole-garment knitting technology and the air breakdown effect. This design allows direct application without complex post-processing and eliminates the need for external rectification. A single unit of KF DC-TENG (8 × 2.5 cm²), after structural optimization, is capable of lighting 744 series-connected Light Emitting Diodes (LEDs) when manually rubbed against polytetrafluoroethylene (PTFE) fabric. Integration with a low-cost power management circuit (PMC, ~1.5 CNY) further enhances the output power by 290 times. As a result, 17 s of friction can power an electronic watch for up to 8 min. Moreover, continuous sliding can sustain a 1.5 W LED without noticeable flickering. This work presents the first demonstration of integrating whole-garment knitting technology with DC-TENGs, offering a scalable and cost-effective strategy for self-powered wearable electronics.

Electrocatalysts for the hydrogen evolution reaction (HER) are critical for sustainable hydrogen production, yet simultaneously achieving high activity, atom-efficient noble-metal use and integrated fabrication remains challenging. Herein, we report a scalable strategy for fabricating integrated electrodes by combining 3D-printed hydrogel templating with ultrafast pulsed Joule heating. In detail, a 3D-printed hydrogel scaffold is transformed into an oxygen-functional hierarchical carbon support that anchors oxygen-coordinated Pt single atoms (SAs) with finely dispersed Pt nanoparticles (NPs). The resulting integrated SA/NP hybrid electrode exhibits greatly increased surface area and a micro-mesoporous architecture, which suppresses NP agglomeration, increases active-site density and improves charge transfer. First-principles calculations reveal that Pt NP primarily drives water dissociation and H^* generation, while adjacent Pt SA enhances the active-site utilization of Pt NP and facilitates OH^* transfer, together accelerating the HER pathway. As a result, the fabricated electrode delivers low overpotentials of 33, 103, and 173 mV at current densities of 10, 50, and 100 mA cm^-2, respectively, while also demonstrating remarkable durability. Beyond providing a practical route to atom-efficient HER electrodes, this integrated strategy uniquely combines a 3D-printed topological scaffold with ultrafast Joule heating to achieve synergistic Pt SA/NP sites, significantly enhancing both structural stability and catalytic kinetics, offering a great promise for next-generation energy-catalysis technologies.