Selective recovery of metals in spent batteries by electrochemical precipitation to cathode material for sodium-ion batteries.

The recycling of key components in waste lithium-ion batteries (LIBs) is an important route to make up for the shortage of battery materials. Metal separation and purification is an important step. It is of great significance to propose an efficient and green separation technology. In this paper, an electrochemical precipitation method was applied to metal separation from spent LiNi0.5Mn1.5O4 cathode material. The Li and metal elements were effective separated and the precipitates were then used as precursor to synthesize high-performance R-O3-NaNFM cathode material for sodium-ion batteries. The R-O3-NaNFM exhibits excellent electrochemical cycling stability. The capacity retains 71.3 mAh g-1 after a long-term cycling of 200 times at 1 C. This method offers a referable strategy of the recycling for the waste cathode material in spent LIBs.

Room-Temperature Processed Annealing-Free Printable Carbon-Based Mesoscopic Perovskite Solar Cells with 17.34% Efficiency.

Carbon-based printable mesoscopic perovskite solar cells (MPSCs) have promising commercial development due to the use of easily scalable printing processes and low-cost carbon material electrodes. Simplifying the preparation process of MPSCs will undoubtedly contribute to their practical application. Here, we demonstrate that efficient and stable MPSCs can be prepared at room temperature without annealing by using low boiling point 2-methoxyethanol (2-ME) and strongly coordinated N-methyl-2-pyrrolidone (NMP) as a novel mixed solvent under the synergistic effect of ammonium chloride (NH4Cl). The results show that the 2-ME/NMP mixed solvent can generate an optimized coordination environment so that uniform nucleation and crystallization of perovskites in mesopores can be achieved at room temperature without annealing by forming uniform small-sized colloids in the precursor solution. Moreover, our work for the first time introduces NH4Cl as a crystallization modulator during a room-temperature annealing-free process, effectively regulating the crystallization behavior of perovskite in mesopores and obtaining high-quality perovskites. Finally, MPSCs prepared synergistically by a room-temperature annealing-free process based on a low boiling point 2-ME/NMP mixed solvent and NH4Cl modulator achieved a champion power conversion efficiency of 17.34% while demonstrating excellent long-term air stability for over half a year. This work provides a new approach to simplifying the preparation process of MPSCs and preparing efficient and stable MPSCs through a room-temperature annealing-free process.

Green Synergy Conversion of Waste Graphite in Spent Lithium-Ion Batteries to GO and High-Performance EG Anode Material.

The increasing demand for graphite and the higher lithium content than environment abundance make the recycling of anode in spent lithium-ion batteries (LIBs) also become an inevitable trend. This work proposes a simple pathway to convert the retired graphite to high-performance expanded graphite (EG) under mild conditions. After the oxidation and intercalation by FeCl3 for the retired graphite, H2 O2 molecules are more likely to penetrate into the extended layers. And the gas phase diffusion caused by the produced O2 from the redox reaction between FeCl3 and H2 O2 further promotes lattice expansion of interlayers (0.535 nm), which is beneficial to the stripping of graphene oxide (GO) with fewer layers. The EG exhibits excellent electrochemical performances in both LIBs and sodium-ion batteries (SIBs). It delivers 331.5 mAh g-1 at 3C (1C = 372 mA g-1 ) in LIBs, while it achieves 176.8 mAh g-1 at 3C (1C = 120 mA g-1 ) in SIBs. Then the capacity retains 753.6 (LIBs) and 201.6 (SIBs) mAh g-1 after a long-term cycling of 500 times at 1C, respectively. The full cells with the EG electrodes after prelithium/presodiation also show excellent cycle stability. Thus, this work offers another referable strategy for the recycling of waste graphite in spent LIBs.

Nickel Acetate-Assisted Graphitization of Porous Activated Carbon at Low Temperature for Supercapacitors With High Performances.

Catalytic graphitization opens a route to prepare graphitic carbon under fairly mild conditions. Biomass has been identified as a potentially attractive precursor for graphitic carbon materials. In this work, corn starch was used as carbon source to prepare hollow graphitic carbon microspheres by pyrolysis after mixing impregnation with nitrate salts, and the surface of these carbon microspheres is covered with controllable pores structure. Under optimal synthesis conditions, the prepared carbon microspheres show a uniform pore size distribution and high degree of graphitization. When tested as electrode materials for supercapacitor with organic electrolyte, the electrode exhibited a superior specific capacitance of 144.8 F g-1 at a current density of 0.1 A g-1, as well as large power density and a capacitance retention rate of 93.5% after 1,000 cycles in galvanostatic charge/discharge test at 1.0 A g-1. The synthesis extends use of the renewable nature resources and sheds light on developing new routes to design graphitic carbon microspheres.