Xin Wu,Jie Zhong,Houji Liu,Yuxi Ren,Haiquan Zhang,Zijing Liu,Ning Wang
Based on the large extraction efficiency of 10–200 μg cm −2 h −1 , the electrolysis-based technology is one of the most promising methods for large-scale extraction of lithium resources from natural seawater. The high potential safety hazard is the inherent defect of the conventional two-electrode electrolytic cell because of the threshold voltage of 3.9 V, which is very close to the decomposition voltage of carbonate electrolytes (4.5–5.0 V). Herein, we designed a novel triple-electrode device, using spinel Li 4 Ti 5 O 12 and 1 M LiPF 6 /FEC + FEMC + HFE respectively as a temporary carrier for storing Li-ions and perfluorinated electrolyte. The threshold voltage of the multi-electrode device is lowered to 2.3 V, which expands the electrochemical window for lithium resource extraction from 1.1 V to 2.7 V. LTO electrode carrier is impossible to electrocatalyze the as-prepared fluoride electrolyte; the compound electrolyte is chemically stable to Li metal as well, avoiding the formation of lithium dendrites . Therefore, the Li 4 Ti 5 O 12 /Li battery exhibits outstanding cycle performances of 99.3% Coulombic efficiency and 95% capacity retention during 250 cycles. Multi-electrode electrochemical devices have shown high safety, stability and extraction efficiency in the practice of extracting Li metal from natural seawater, which is very beneficial to the development of marine mineral resources.
Quansheng Li,Xuesong Mei,Xiaofei Sun,Yanbin Han,Bin Liu,Zikang Wang,Anastase Ndahimana,Jianlei Cui,Wenjun Wang
Owing to their excellent structural superiorities of large storage space, high specific surface area and reduced volume expansion during battery charge and discharge cycles, 3D porous current collectors have received much concern in the anode of lithium-ion batteries. However, reasonable designing and efficient manufacturing of 3D porous copper foils as current collectors (PCFCCs) remain a great challenge due to the small thickness, soft texture, and variability of copper foils. These material characteristics make it hard to manufacture 3D micro-structure on copper foils and impede the practical application of lithium-ion batteries in more fields. Herein, an efficient and effective strategy is reported to enhance the electrochemical performance of Li 4 Ti 5 O 12 (LTO) electrodes via rationally designing and manufacturing 3D porous copper foils as current collectors. As a result, the 3D PCFCCs based LTO electrode displays low electrode polarization, excellent-cycle performance and ultra-high rate capacity. Moreover, the structures of various 3D PCFCCs are systematically studied for the first time, the design of 3D PCFCCs is optimized, and the mechanism of improving battery performance is explored. In addition, the proper micro-nano-pore-structures can facilitate electrolyte penetration and the solvated Li + transport, and the excellent Li + transmission ability of 3D PCFCCs is verified by simulation.
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