Clean Universal Solid-State Recovery Method of Waste Lithium-Ion Battery Ternary Positive Materials and Their Electrochemical Properties

Abstract

The regeneration and utilization of metallic elements in waste lithium-ion batteries (LIBs) have caused growing notice from researchers and battery manufacturers because of the increasing amount of waste LIBs and limited lithium resources. In this work, we propose a novel valuable metal leaching system in waste positive materials of LIBs via a recyclable clean solid-state conversion method, which was simple and easy to realize a high utilization rate of waste resources. In this leaching system, approximately neutral ammonium sulfate solid was used as the bifunctional leaching agent based on reduction and acidification in the leaching procedure of ternary positive materials (NCMs). The roasting process of (NH4)2SO4 and NCMs was followed by the main metallic elements in NCMs being transformed into soluble sulfates, which could be completely leached in the water leaching procedure. The roasting–leaching process parameters were systematically investigated on the molar ratio, roasting temperature, and time. Under optimal conditions, all the leaching rates of Ni, Co, Mn, and Li achieved 99%. After generating sulfate solution by water leaching, the spherical ternary material precursor was co-precipitated with a (NH4)2CO3 precipitant, and the formed (NH4)2SO4 was recycled for the next batch, thus achieving a green and low cost recyclable route. The re-synthesized LiNi1/3Co1/3Mn1/3O2 (NCM111) with homogeneous size particle distribution and good layered hexagonal structure of α-NaFeO2 was obtained as a cathode material after high-temperature calcination with uniform particle size distribution and intact layered structure with a hexagonal crystal system of α-NaFeO2, which well meets the commercial requirements for LIBs in terms of electrochemical properties.

Insight into the Role of Co and Mn Elements in Ni-Rich LiNi0.9CoxMn0.08–xAl0.02O2 Cathode Materials

“…To analyze the influence of Co and Mn elements on the crystal structure of the four-element cathode material, we performed XRD analysis on samples NCMA9712, NCMA9532, and NCMA9352, the results of which are shown in Figure a. All the samples belong to the hexagonal α-NaFeO 2 layered structure with the space group R 3̅ m , which indicates that the crystal structure of the material is essentially not affected by the change of the content of Co and Mn. , In addition, all samples showed clear (006)/(102) and (108)/(110) peak splits, indicating an ordered layered structure. , It can be seen from Figure b that with the gradual increase of the cobalt content, the peak of (003) gradually shifts to a lower angle. The reason may be that the atomic radius of Co 3+ (0.054 nm) is larger than that of Mn 4+ (0.053 nm), increasing the lattice spacing of the (003) plane. , …”

“…All the samples belong to the hexagonal α-NaFeO 2 layered structure with the space group R3̅ m, which indicates that the crystal structure of the material is essentially not affected by the change of the content of Co and Mn. 37,38 In addition, all samples showed clear (006)/(102) and (108)/(110) peak splits, indicating an ordered layered structure. 39,40 It can be seen from Figure 2b that with the gradual increase of the cobalt content, the peak of (003) gradually shifts to a lower angle.…”

Cathode regeneration and upcycling of spent LIBs: toward sustainability

“…Cathode recycling techniques can be classified into indirect recycling and direct regeneration. 15,[22][23][24] The former is aimed at salvaging chemical elements, such as lithium, nickel, and cobalt, using pyrometallurgy or hydrometallurgy; [25][26][27][28][29][30] the latter is dedicated to restoring the chemical composition, crystalline structure, and morphology of the cathode particles without particle destruction during processing. [31][32][33] The primary routes for the processes involved in these two recycling methods are presented in Fig.…”

Regenerated Ni-Doped LiCoO2 from Spent Lithium-Ion Batteries as a Stable Cathode at 4.5 V

“…Recently, some salt-assisted roasting processes have been developed to reduce the decomposition temperature of cathode materials, thereby enhancing metal recovery rates. For instance, Pan et al utilized (NH 4 ) 2 SO 4 for the roasting and water leaching process to convert ternary cathode material (NCM) into sulfate, achieving leaching rates of 99% for Li, Co, Ni, and Mn . These studies have to an extent reduced energy consumption and the usage of strong acids and bases in the recovery process.…”