Ever-growing global energy needs and environmental damage have motivated the pursuit of sustainable energy sources and storage technologies. As attractive energy storage technologies to integrate renewable resources and electric transportation, rechargeable batteries, including lead-acid, nickel-metal hydride, nickel-cadmium, and lithium-ion batteries, are undergoing unprecedented rapid development. However, the intrinsic toxicity of rechargeable batteries arising from their use of toxic materials is potentially environmentally hazardous. Additionally, the massive production of batteries consumes numerous resources, some of which are scarce. It is therefore essential to consider battery recycling when developing battery systems. Here, we provide a systematic overview of rechargeable battery recycling from a sustainable perspective. We present state-of-the-art fundamental research and industrial technologies related to battery recycling, with a special focus on lithium-ion battery recycling. We introduce the concept of sustainability through a discussion of the life-cycle assessment of battery recycling. Considering the forecasted trend of a massive number of retired power batteries from the forecasted surge in electric vehicles, their repurposing and reuse are considered from economic, technical, environmental, and market perspectives. New opportunities, challenges, and future prospects for battery recycling are then summarized. A reinterpreted 3R strategy entailing redesign, reuse, and recycling is recommended for the future development of battery recycling.

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Rapid development of energy storage system causes a burst demand of lithium-ion batteries (LIBs), and large number of spent LIBs with high valuable metals are produced. Here we propose a novel application of oxalic acid leaching to regenerate Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 (NCM) cathodes from spent LIBs. With lithium dissolving into the solution, the transition metals transform into oxalate precipitates and deposit on the surface of spent NCM cathodes, separating lithium and transition metals in one simple step. After mixing with certain amount of Li 2 CO 3 , the oxalate precipitates together with unreacted NCM are directly calcined into new NCM cathodes. The regenerated NCM after 10 min leaching exhibits the best electrochemical performances, delivering the highest initial specific discharge capacity of 168 mA h g −1 at 0.2C and 153.7 mA h g −1 after 150 cycles with a high capacity retention of 91.5%. The excellent electrochemical performances are attributed to the submicrometer particles and voids after calcination, as well as the optimal proportion of elements. This process can make the most of valuable metals in the spent cathodes, with >98.5% Ni, Co, and Mn recycled. It is simple and effective, and provides a novel perspective of recycling cathodes from spent LIBs.

Recycling of spent LiFePO 4 batteries has drawn recent attention relating to recovering their high contents of rare elements and negating potential negative environmental effects of their disposal. However, the stable crystal structure of LiFePO 4 materials has prevented the development of a recycling process with high selectivity and extraction efficiency. We report the selective extraction of Fe and Li from spent LiFePO 4 batteries via an environmentally friendly mechanochemical process with oxalic acid. With the use of a mechanochemical treatment and water leaching, the Li extraction efficiency can be improved to 99%. Furthermore, 94% of Fe can be simultaneously recovered as FeC 2 O 4 •2H 2 O. To understand the reaction mechanism and determine the optimum reaction conditions, we investigated various parameters, including the LiFePO 4 to oxalic acid mass ratio, rotation speed, milling time, and ball-to-powder mass ratio. Moreover, metal ions from the water leaching process were recovered by chemical precipitation. This study provides an efficient and selective process for recovery of valuable metals from spent LiFePO 4 materials.

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The autonomous navigation of greenhouse robots depends on precise mapping, accurate localization information and a robust path planning strategy. However, the complex agricultural environment introduces significant challenges to robot perception and path planning. In this study, a hardware system designed exclusively for greenhouse agricultural environments is presented, employing multi-sensor fusion to diminish the interference of complex environmental conditions. Furthermore, a robust autonomous navigation framework based on the improved LeGO-LOAM and OpenPlanner has been proposed. In the perception phase, a relocalization module is integrated into the LeGO-LOAM framework. Comprising two key steps - map matching and filtering optimization, it ensures a more precise pose relocalization. During the path planning process, ground structure and plant density are considered in our Enhanced OpenPlanner. Additionally, a hysteresis strategy is introduced to enhance the stability of system state transitions.The performance of the navigation system in this paper was evaluated in several complex greenhouse environments. The integration of the relocalization module significantly decreases the Absolute Pose Error (APE) in the perception process, resulting in more accurate pose estimation and relocalization information. Moreover, our Enhanced OpenPlanner exhibits the capability to plan safer trajectories and achieve more stable state transitions in the experiments. The results underscore the effectiveness and robustness of our proposed approach, highlighting its promising application prospects in autonomous navigation for agricultural robots.