Recycling of spent lithium-ion batteries to resynthesize high-performance cathode materials for sodium-ion storage

The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the weaker pollution and fewer profits of LiMn2O4 cathode dispel the enthusiasm and responsibility of industry companies.Thus,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn2O4 materials for the profit improvement is proposed.In detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn2O4 spinel structure is destroyed within a short period time and transformed into simple metal oxide.As anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.% of manganese can be extracted in acid solution.Noted that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling process.The regenerated Na0.67Ni0.3Mn0.7O2 cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g-1,and the retention rate reached 98.3% after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn2O4 aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.