A paradigm-shift lithium-ion battery recycling method based on defect-targeted healing can fully recover the composition, structure, and electrochemical performance of spent LiFePO4 cathodes with various degradation conditions to the same levels as that of the pristine materials. Such a direct recycling approach can significantly reduce energy usage and greenhouse gas emissions, leading to significant economic and environmental benefits compared with today's hydrometallurgical and pyrometallurgic methods. This work may pave the way for industrial adoption of directly recycled lithium-ion battery materials.

Electrochemical synthesis of H 2 O 2 through a selective two-electron (2e −) oxygen reduction reaction (ORR) is an attractive alternative to the industrial anthraquinone oxidation method, as it allows decentralized H 2 O 2 production. Herein, we report that the synergistic interaction between partially oxidized palladium (Pd δ+) and oxygen-functionalized carbon can promote 2e − ORR in acidic electrolytes. An electrocatalyst synthesized by solution deposition of amorphous Pd δ+ clusters (Pd 3 δ+ and Pd 4 δ+) onto mildly oxidized carbon nanotubes (Pd δ+-OCNT) shows nearly 100% selectivity toward H 2 O 2 and a positive shift of ORR onset potential by~320 mV compared with the OCNT substrate. A high mass activity (1.946 A mg −1 at 0.45 V) of Pd δ+-OCNT is achieved. Extended X-ray absorption fine structure characterization and density functional theory calculations suggest that the interaction between Pd clusters and the nearby oxygen-containing functional groups is key for the high selectivity and activity for 2e − ORR.

Lithium metal batteries are capable of pushing cell energy densities beyond what is currently achievable with commercial Li-ion cells and are the ideal technology for supplying power to electronic devices...

Direct regeneration of spent Li-ion batteries based on the hydrothermal relithiation of cathode materials is a promising next-generation recycling technology. In order to demonstrate the feasibility of this approach at a large scale, we systematically design and optimize the process parameters to minimize both energy and raw material costs. Specifically, the effects of regenerative processing parameters on the composition, structure, and electrochemical performance of the regenerated cathode materials are investigated via systematic characterization and testing. From this analysis, it was found that the raw material costs can be substantially reduced by either replacing the typically employed 4 M LiOH solution by a cost-effective mixture of 0.1 M LiOH and 3.9 M KOH or recycling of the concentrated 4 M LiOH for continuous relithiation processes. Life cycle analysis suggests that this strategy results in reduced energy consumption and greenhouse gas emissions, leading to an increased potential revenue, particularly when compared with hydro-and pyrometallurgical recycling methods.

Due to the large demand of lithium-ion batteries (LIBs) for energy storage in daily life and the limited lifetime of commercial LIB cells, exploring green and sustainable recycling methods becomes an urgent need to mitigate the environmental and economic issues associated with waste LIBs. In this work, we demonstrate an efficient direct recycling method to regenerate degraded lithium manganese oxide (LMO) cathodes to restore their high capacity, long cycling stability, and high rate performance, on par with pristine LMO materials. This one-step regeneration, achieved by a hydrothermal reaction in dilution Li-containing solution, enables the reconstruction of desired stoichiometry and microphase purity, which is further validated by testing spent LIBs with different states of health. Life-cycle analysis suggested the great environmental and economic benefits enabled by this direct regeneration method compared with today's pyro-and hydrometallurgical processes. This work not only represents a fundamental understanding of the relithiation mechanism of spent cathodes but also provides a potential solution for sustainable and closed-loop recycling and remanufacturing of energy materials.

As lithium-ion batteries (LIBs) become vital energy source for daily life and industry applications, a large volume of spent LIBs will be produced after their lifespan. Recycling of LIBs has been considered as an effective closed-loop solution to mitigate both environmental and economic issues associated with spent LIBs. While reclaiming of transition metal elements from LIB cathodes has been well established, recycling of graphite anodes has been overlooked. Here, we show an effect upcycling method involving both healing and doping to directly regenerate spent graphite anodes. Specifically, using boric acid pretreatment and short annealing, our regeneration process not only heals the composition/structure defects of degraded graphite but also creates functional boron-doping on the surface of graphite particles, providing high electrochemical activity and excellent cycling stability. The efficient direct regeneration of spent graphite by using low cost, non-volatile and non-caustic boric acid with low annealing temperature provides a more promising direction for green and sustainable recycling of spent LIB anodes.

Silicon has attracted considerable interest as a high-capacity anode material for next-generation lithium-ion batteries. However, Si-based anodes suffer extreme volume change (≈380%) upon lithiation and delithiation, which results in rapid capacity fading due to mechanical and electrochemical failure during cycling. Herein, a sustainable and scalable method to synthesize hierarchically porous micron-sized Si particles from the low-cost diatomite precursor is reported, which serves as both the precursor and the template. Through a one-step magnesiothermic reduction, the SiO 2 constituent in diatomite is reduced to form a Si/SiO 2 composite network with 10-30 nm crystalline Si domains embedded within an amorphous SiO 2 matrix. Controlling the reduction time leads to an optimal ratio between the crystalline Si and the amorphous SiO 2 constituent, which endows the composite structure with high capacity and excellent cycling stability. For example, 90% capacity can be retained after 500 cycles at 0.2C for sample reduced by 6 h without any coating or prelithiation. The full cell with such Si/SiO 2 as the anode and LiNi 0.8 Co 0.1 Mn 0.1 O 2 as the cathode shows ≈80% capacity retention after 200 cycles. This work creates a unique path towards sustainable and scalable production of high-performance micron-sized Si anodes, offering new opportunities for potential industrial applications.

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