The massive adoption of electric vehicles and the depletion of limited metal resources make lithium-ion batteries (LIBS) imperative, but the current licoo2 pathway is mainly pyrometallurgical and wet, with large energy input and extensive processing, so there is an urgent need for alternative multi-functional and green methods. Based on this,Academician Yu Jihong of Jilin University, Professor Mei Donghai of Tianjin Polytechnic University and Professor Zhang Wei of Soochow University (co-corresponding author) and othersAn ingenious and versatile strategy is reported to reconstruct **libs through catalysts, using hydrogen evolution reaction (HER) as a proof of concept. The Li ion cathode catalyzes the reaction, and the catalyst reforms hydroxides to promote the complete extraction of metals (such as Li, Co, Ni, Mn, Fe), and the leaching efficiency is close to 100%. Mechanistic studies have shown proton or hydroxide ion-assisted catalyst remodeling**. This green hydrogen coupling** method is generally suitable for licoo2, lini08mn0.1co0.1o2、lini0.33mn0.33co0.33o2、lini0.8co0.15al0.All major cathode types such as 05O2, Limn2O4, LiFePO4, including polyanion, layered and spinel oxides, and scalable to actual waste bag batteries, offer a versatile and sustainable alternative to traditional methods with a wide range of implications beyond batteries**.
Lithium-ion batteries (LIBS) are widely used in portable electronics, electric vehicles, and large-scale energy storage systems for smart grids, with most used LIBS currently going to landfills, and less than 6% of LIBS worldwide being utilized. The use of LIBS not only eliminates potential environmental pollution, but also allows for the reuse of valuable metals. However, existing LIBS** technologies are not economically or environmentally sustainable. Currently, the ** method relies on pyrometallurgy and hydrometallurgy to extract metals from cathode materials at high temperatures (1400 °C) to reduce transition metal oxides to their alloys and entrainment of LI in the slag, but it still faces adverse high energy and capital costs, loss of gaseous pollutants and LI. Hydrometallurgical treatment uses strong acids and reducing agents to leach metals in a low-price state, but the technology often involves complex pretreatment processes and environmental concerns with strong acid reagents.
Electrochemical reduction is limited to specific cathode materials and is not suitable for polyanionic cathodes with lower valence transition metals (TMS). In addition, these processes are mainly for the value of CO, and the cathode material is one or a mixture of LiCoO2, LiFePO4, Limn2O4, LinixMnyCozo2 and LinixCoyalzo2 (X + Y + Z = 1). Therefore, the development requires a universal green metal approach to all cathode materials, but it is also challenging.
Battery cathode **metalIn this study, it was found through scanning electron microscopy (SEM) and energy spectroscopy (EDS) elemental characterization that LicoO2 (LCO) was first tightly surrounded by carbon black, then a large gap appeared between LCO and carbon black, and finally LCO could not be identified on the foil, leaving a large number of pits in the original position. Li+ was detected immediately after the reaction, and CO2+ was detected only after the reaction time reached 7 min, indicating that the dissolution of cobalt lagged slightly behind Li. As the reaction progresses, the size of the LFP particles gradually decreases and eventually disappears on the foil. As the reaction time is extended, their concentration increases rapidly, reaching a maximum at 12 h with a leaching rate of about 100%. The XRD peak of LFP also gradually weakened, and no new peak was found, indicating that LFP had undergone structural reconstruction during the catalytic reaction.
Figure 1Compare different lib** methods
Figure 2Metal leaching of LCO and LFP as HER catalystsCatalyst reconstitution of cathode materials
After HER is catalyzed, the surface layer of LCO begins to transform into an amorphous structure. The peak of layered LCO around 530 EV disappeared after 10 min, indicating that the layered structure of the LCO surface was destroyed immediately after the catalytic reaction. Density functional theory (DFT) simulations show that the structural transformation of LCO to CO(OH)2 induced by proton insertion is the most favorable energy pathway. The transition metal of LFP is in a low-valence state and is also reconstituted into hydroxides during the catalytic reaction, eliminating the possible effects of electron reduction. The results show that for LCO, protons are inserted during the catalytic reaction, resulting in degradation of the lamellar structure, loss of LI, etching of CO in a weakly acidic solution. In the LFP catalyst, hydroxide ions replace phosphate and Li ions, resulting in a structural transformation to amorphous iron hydroxide, which is subsequently dissolved in solution.
Figure 3Reconstitution of LCO and LFP catalystsExtensions in various lib systems
In this paper, LMO, LNC811, LNC111, LNCA, and LFMP cathode materials were used as HER catalysts, and their structures were transformed into corresponding hydroxides, which were conducive to the extraction of Li and TMS, with a leaching efficiency of nearly 100%. In addition, the authors use commercial scrap lini05mn0.3co0.2O2 (LNMC532) graphite pouch battery as proof of concept. After disassembly, LNMC532 acts as a working electrode for catalytic HER. During the catalytic reaction, the LNMC532 particles gradually become smaller and eventually disappear. The leaching efficiency of LI and TMS showed that the high loading capacity (328 mg cm2) of the commercial LNMCC532 cathode can also be fully leached. After total leaching, the TMS is collected in the form of alloys or salts by simultaneous electrodeposition or precipitation, the LI is collected in the form of lithium salts, and the residual aluminum foil and carbon black are also easily separated and **.
Figure 4Expand to other positive electrodes
Figure 5Waste bag battery LMMC532**
complete metal recycling from lithium-ion batteries enabled by hydrogen evolution catalyst reconstruction. j. am. chem. soc.,