Direct reuse of oxide scrap from retired lithium‐ion batteries: advanced cathode materials for sodium‐ion batteries

The direct reuse of retired lithium‐ion batteries (LIBs) cathode materials is one of the optimum choices for “waste‐to‐wealth” by virtue of sustainable and high economic efficiency. Considering the harmfulness of retired LIBs and the serious shortage of lithium resources, in this work, the spent oxide cathode materials after simple treatment are directly applied to the sodium‐ion batteries (SIBs) and exhibit promising application possibilities in advanced SIBs. The spent oxide cathode shows an appropriate initial discharge capacity of 109 mAh·g −1 and exhibits transition and activation processes at a current density of 25 mA·g −1 . Further, it demonstrates decent cycle performance and comparatively good electrode kinetics performance (the apparent ion diffusion coefficient at steady state is about 1 × 10 –12 cm 2 ·s −1 ). The “waste‐to‐wealth” concept of this work provides an economical and sustainable strategy for directly reusing the retired LIBs and supplies a large amount of raw material for the large‐scale application of SIBs.