RESUMEN
The aggravated mechanical and structural degradation of layered oxide cathode materials upon high-voltage charging invariably causes fast capacity fading, but the underlying degradation mechanisms remain elusive. Here we report a new type of mechanical degradation through the formation of a kink band in a Mg and Ti co-doped LiCoO2 cathode charged to 4.55 V (vs Li/Li+). The local stress accommodated by the kink band can impede crack propagation, improving the structural integrity in a highly delithiated state. Additionally, machine-learning-aided atomic-resolution imaging reveals that the formation of kink bands is often accompanied by the transformation from the O3 to O1 phase, which is energetically favorable as demonstrated by first-principles calculations. Our results provide new insights into the mechanical degradation mechanism of high-voltage LiCoO2 and the coupling between electrochemically triggered mechanical failures and structural transition, which may provide valuable guidance for enhancing the electrochemical performance of high-voltage layered oxide cathode materials for lithium-ion batteries.
RESUMEN
Physical properties of materials are mainly determined by valence electron configurations, where different valence shells would induce divergent phenomena. In compounds containing Sc2+ , 3d electron occupancy is expected, the same as other transition metal atoms like Ti3+ . But this situation still awaits experimental verification in inorganic materials. Here, we selected ScS to measure the valence electron density and orbital population of Sc2+ through delicate quantitative convergent-beam electron diffraction. With the absence of 3d orbital features around Sc-atom sites and the nearly bare population of t2g orbital, the unintuitive occupation of 4s orbital in Sc2+ is concluded. It should be the first time to report such a special electron configuration in a transition metal compound, in which 4s rather than 3d orbital is preferred. Our findings reveal the distinct behavior of Sc and probable ways to modulate material properties by controlling electron orbitals.
RESUMEN
Objective: This study investigates the efficacy of physical therapy in treating chronic prostatitis grounded on the glandular duct blockage theory. Methods: The study includes patients who were diagnosed and treated for chronic prostatitis between November 2022 and July 2023 at Renhui clinic in Jiangmen, Guangdong and Renhui frontline clinic in Shenzhen Guangdong. The recorded data includes the frequency of physical therapies including prostate massages, rectal probe high-frequency vibration treatment, and low-intensity extracorporeal shockwave therapy (Li-ESWT). Post-treatment urine sediment was collected for microscopic examination, and the scores of each patient on the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and the Premature Ejaculation Diagnostic Tool (PEDT) were recorded pre- and post-treatment in order to calculate the effectiveness rate. Results: The study involved a total of 48 patients, of which 26 were diagnosed with premature ejaculation. On average, each patient received 2.1 prostate massages, underwent 4.1 rectal probe high-frequency vibration treatments, and 8.3 Li-ESWT sessions. Following treatment, the initial microscopic examination of the urine sediment revealed aged white blood cell clusters, prostate calculi clusters, and inactive sperm clusters, all appearing in the shape of glandular tubes. The mean NIH-CPSI scores pre- and post-treatment were 27.2±6.9 and 18.0±6.6, respectively, indicating an effectiveness rate of 81.3%. The average PEDT scores pre- and post-treatment were 14.5±3.5 and 10.5±4.2, respectively, with an effectiveness rate of 53.8%. Conclusion: Unblocking obstructed glandular ducts might provide a novel therapeutic strategy for treating chronic prostatitis.