Grain boundary hinge structure design for upcycling of cathode materials from spent lithium-ion batteries

The recycling of spent lithium-ion batteries in a scientific and efficient manner is expected to address resource scarcity and reduce environmental pollution. Currently, conventional direct regeneration methods are difficult to simultaneously repair the particles, crystal structure, and interface of spent Lithium cobalt oxide (LCO) in three dimensions. This work adopts a "disintegrate-mend" reshaping approach to construct a localized heterogeneous hinge structure, grain boundary gradient crystal phases, and uniform polycrystalline particles, thereby achieving a unique structure for regenerated LCO materials. This design overcomes the limitations of uneven degradation in spent LCO, enhances the three-dimensional electron shuttle behaviour of the regenerated material, suppresses the redox activity of lattice oxygen, and optimizes spin-orbital coupling effects. Consequently, the regenerated LCO material demonstrates exceptionally high discharge capacity, with an initial discharge specific capacity of 228.94 mAh g −1 . Moreover, the soft-packed batteries demonstrate outstanding cycle stability, with capacity retentions of 95.94% after 500 cycles. • The multi-scale collaborative reshaping and upcycling strategy has been proposed. • The unique structure of regenerated cathodes brings excellent performance. • The material regeneration mechanism in the upcycling process was analyzed. • The electrochemical behavior of regenerated materials has also been clarified.