LiFePO₄ is widely used as a stable and environmentally benign cathode material. However, its reuse potential is constrained by recycling challenges and significant performance degradation after decommissioning. Therefore, how to effectively improve the electrochemical performance of regenerated LiFePO₄ materials and enhance their stability during cycling has become the focus of current research. In this research, Sm doping was introduced to optimize regenerated LiFePO₄ cathode materials via a plasma ball milling assisted solid-state calcination method. Comparison between spent LiFePO₄ and Sm-doped regenerated cathodes revealed that the appropriate level of Sm doping effectively maintained the crystal structure of LiFePO₄. It also promoted a more uniform particle morphology and a reduced particle size, which is beneficial for shortening Li⁺ transport pathways. This enhancement significantly improved electronic conductivity, leading to enhanced electrochemical performance. The 2% Sm doped regenerated material exhibited optimal performance, achieving an initial charge-discharge specific capacity of 142.2 mAh·g^–1 at 1 C and maintaining a capacity retention of 96.5% after 200 cycles. This conclusion is of significant importance for improving resource utilization efficiency of spent LiFePO₄ batteries.

Amid the escalating global environmental and energy crises, sodium-ion batteries (SIBs) are emerging as a significant complement to lithium-ion batteries (LIBs), owing to their high voltage platform, excellent safety, wide temperature range, and low cost. The choice of cathode materials plays a crucial role in influencing the efficiency and effectiveness of SIBs. Although layered cathode materials have shown promising prospects in specific capacity, voltage range, and environmental friendliness, they still face significant challenges due to factors like poor stability in air, interface degradation, and irreversible structural changes. Despite the low immediate economic benefits, the recycling of used SIBs has not been sufficiently addressed. As the adoption of SIBs grows, their recycling will present significant environmental and resource challenges in the future. This review starts with the synthesis of layered cathodes in SIBs and examines the failure mechanisms and improvement strategies during manufacturing and cycling, extending to the recovery of spent batteries. Through a comprehensive analysis, we aim to provide theoretical support and technical guidance for constructing the full life cycle value chain of new energy. The analysis in this paper includes innovations in materials and recycling technologies, extending to considerations of societal, ethical, and environmental aspects, especially how to balance corporate profits and social responsibility, and how recycling technologies can maximize resource utilization and environmental protection. Additionally, this review proposes a complete closed-loop system from production to recycling, emphasizing the sustainability of SIBs technology throughout its entire life cycle, offering a systematic framework and development direction for the future application of SIBs.

Affected by cobalt (Co) supply bottlenecks and high costs, Co-free Ni-rich layered cathodes are considered the most promising option for economical and sustainable development of lithium-ion batteries (LIBs). Low-cost LiNi_xAl_1−xO₂ (x ≥ 0.9) cathode are rarely reported due to their chemo-mechanical instabilities and poor cycle life. Herein, we employ a strategy of Mg/W Li/Ni dual-site co-doping LiNi_0.9Al_0.1O₂ (named as LNA90) cathodes to enhance cycling stability by modifying the crystal structure and forming a center radially aligned microstructure. The Mg/W co-doped LiNi_0.9Al_0.1O₂ cathode (named as LNAMW) exhibits high capacity retention of 94.9% at 1 C and 3.0–4.5 V after 100 cycles with 22.0% increase over the pristine cathode LNA90 and maintains the intact particle morphology. Meanwhile, the cycling performance of LNAMW cathode exceeds that of most reported Ni-rich cathodes (Ni mol% > 80%). Our work offers a straightforward, efficient, and scalable strategy for the future design of Co-free Ni-rich cathodes to facilitate the development of economical lithium-ion batteries.