Spent LiFePO batteries will surge soon due to the global trend towards adopting electric vehicles. The recycling of the batteries leaves low value FePO dominated waste (FPW), which is currently not efficiently repurposed. This study aims to reveal the characteristics of FPW, investigate its effects on cement hydration, and explore potential applications in the concrete industry. FPW was used to replace cement at increased ratios up to 10%. The results showed that a suitable dosage of the battery waste (e.g. 5%) enabled the blended cement binder to achieve refined pore structure and enhanced 7- and 28-day compressive strength. FePO reacted in cement binder which consumes crystal CH and generates amorphous hydroxyapatite, potentially leading to microstructure refinement. Additionally, FPW exhibited the potential to be developed as a concrete retarder. Continuous retarding on cement hydration was observed, primarily for CS and CA at an early age of 1 day, and turned to CS and CAF thereafter.

中文翻译：

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低值锂离子电池废料在水泥和混凝土中的可持续利用

由于全球采用电动汽车的趋势，废旧磷酸铁锂电池很快就会激增。电池的回收留下了以磷酸铁为主的低价值废物（FPW），目前尚未有效地重新利用。本研究旨在揭示FPW的特性，研究其对水泥水化的影响，并探索在混凝土行业中的潜在应用。使用 FPW 代替水泥，比例增加至 10%。结果表明，适当的电池废料掺量（如5%）可使混合水泥粘结剂的孔隙结构细化，并提高7天和28天的抗压强度。 FePO 在水泥粘合剂中发生反应，消耗晶体 CH 并生成无定形羟基磷灰石，可能导致微观结构细化。此外，FPW 还展现出开发为混凝土缓凝剂的潜力。观察到水泥水化持续延迟，主要是在 1 天龄初期的 CS 和 CA，此后转向 CS 和 CAF。