No abstract

Fast charging of lithium ion batteries is essential for next‐generation energy‐storage systems. However, the poor ionic and electronic transport of anodes with its rather high mass loading limits the practical applications of this technology. Herein, a multiscale design from niobium titanium oxide anode material to electrode structure is proposed for fast charging lithium ion batteries with a practical level of areal capacity (3 mAh cm−2). At the atomic scale, the introduction of oxygen vacancy and surface carbon coating enables niobium titanium oxide (TiNb2O7−x@C) to possess excellent ionic and electronic conductivity. For the microscopic electrode structure, 1D TiNb2O7−x@C fibers are tightly assembled to form a high‐speed transport network of ions and electrons throughout the electrode. As a result, the obtained TiNb2O7−x@C electrode shows excellent rate capability (1.83 mAh cm−2 at 1 C) and cycling stability under an areal capacity of 3 mAh cm−2 (2.35 mAh cm−2 after 100 cycles at 0.5 C) in half‐cells. Significantly, a full‐cell coupled with practical level mass loading of lithium cobalt oxide cathode is demonstrated to deliver 1.55 mAh cm−2 at 3 C for the first time.

Solid electrolytes (SEs) with superionic conductivity and interfacial stability are highly desirable for stable all-solid-state Li-metal batteries (ASSLMBs). Here, we employ neural network potential to simulate materials composed of Li, Zr/Hf, and Cl using stochastic surface walking method and identify two potential unique layered halide SEs, named Li 2 ZrCl 6 and Li 2 HfCl 6 , for stable ASSLMBs. The predicted halide SEs possess high Li + conductivity and outstanding compatibility with Li metal anodes. We synthesize these SEs and demonstrate their superior stability against Li metal anodes with a record performance of 4000 h of steady lithium plating/stripping. We further fabricate the prototype stable ASSLMBs using these halide SEs without any interfacial modifications, showing small internal cathode/SE resistance (19.48 Ω cm 2 ), high average Coulombic efficiency (∼99.48%), good rate capability (63 mAh g −1 at 1.5 C), and unprecedented cycling stability (87% capacity retention for 70 cycles at 0.5 C).