Effect of pulse-current-based protocols on the lithium dendrite formation and evolution in all-solid-state batteries

Understanding the cause of lithium dendrites formation and propagation is essential for developing practical all-solid-state batteries. Li dendrites are associated with mechanical stress accumulation and can cause cell failure at current densities below the threshold suggested by industry research (i.e., >5 mA/cm²). Here, we apply a MHz-pulse-current protocol to circumvent low-current cell failure for developing all-solid-state Li metal cells operating up to a current density of 6.5 mA/cm². Additionally, we propose a mechanistic analysis of the experimental results to prove that lithium activity near solid-state electrolyte defect tips is critical for reliable cell cycling. It is demonstrated that when lithium is geometrically constrained and local current plating rates exceed the exchange current density, the electrolyte region close to the defect releases the accumulated elastic energy favouring fracturing. As the build-up of this critical activity requires a certain period, applying current pulses of shorter duration can thus improve the cycling performance of all-solid-solid-state lithium batteries.

Extended solid solutions and coherent transformations in nanoscale olivine cathodes

Nanoparticle LiFePO4, the basis for an entire class of high power Li-ion batteries, has recently been shown to exist in binary lithiated/delithiated states at intermediate states of charge. The Mn-bearing version, LiMn(y)Fe(1-y)PO4, exhibits even higher rate capability as a lithium battery cathode than LiFePO4 of comparable particle size. To gain insight into the cause(s) of this desirable performance, the electrochemically driven phase transformation during battery charge and discharge of nanoscale LiMn0.4Fe0.6PO4 of three different average particle sizes, 52, 106, and 152 nm, is investigated by operando synchrotron radiation powder X-ray diffraction. In stark contrast to the binary lithiation states of pure LiFePO4 revealed in recent investigations, the formations of metastable solid solutions covering a remarkable wide compositional range, including while in two-phase coexistence, are observed. Detailed analysis correlates this behavior with small elastic misfits between phases compared to either pure LiFePO4 or LiMnPO4. On the basis of time- and state-of-charge dependence of the olivine structure parameters, we propose a coherent transformation mechanism. These findings illustrate a second, completely different phase transformation mode for pure well-ordered nanoscale olivines compared to the well-studied case of LiFePO4.

New cyclopropyl-triterpenoids from the aerial roots of Ficus microcarpa

Four new cyclopropyl-triterpenes, 27-nor-3beta-hydroxy-25-oxocycloartane (1), (22E)-25,26,27-trinor-3beta-hydroxycycloart-22-en-24-al (2), 3beta-acetoxy-15alpha-hydroxy-13,27-cyclours-11-ene (3), 3beta-acetoxy-12alpha-formyloxy-13,27-cycloursan-11alpha-ol (4), together with (23E)-27-nor-3beta-hydroxycycloart-23-en-25-one (5) were isolated from the aerial roots of Ficus microcarpa. Compounds 3 and 4 are rare 13,27-cycloursane-type triterpenes. Their structures were elucidated by spectroscopic and chemical methods.

New peroxy triterpenes from the aerial roots of Ficus microcarpa

Six new triterpenes, 3 beta-acetoxy-12 beta,13 beta-epoxy-11 alpha-hydroperoxyursane (1), 3 beta-acetoxy-11 alpha-hydroperoxy-13 alpha H-ursan-12-one (2), 3 beta-acetoxy-1 beta,11 alpha-epidioxy-12-ursene (3), (20S)-3 beta-acetoxylupan-29-oic acid (4), (20S)-3 beta-acetoxy-20-hydroperoxy-30-norlupane (5), and 3 beta-acetoxy-18 alpha-hydroperoxy-12-oleanen-11-one (6), together with 3 beta-acetoxy-12-oleanen-11-one (7), were isolated from the aerial roots of Ficus microcarpa. Compounds 1-3, 5, and 6 were characterized as new peroxytriterpenes. The structures of 3 and 6 were confirmed by X-ray crystallography, and their structures were elucidated by spectroscopic and chemical methods.

Taraxastane-type triterpenes from the aerial roots of Ficus microcarpa

Seven new taraxastane-type triterpenes-20-taraxastene-3beta, 22alpha-diol (1), 3beta-acetoxy-20-taraxasten-22alpha-ol (2), 3beta-acetoxy-22alpha-methoxy-20-taraxastene (3), 3beta-acetoxy-20alpha,21alpha-epoxytaraxastan-22alp ha-ol (4), 3beta-acetoxy-19alpha-methoxy-20-taraxastene (5), 3beta-acetoxy-19alpha-hydroperoxy-20-taraxastene (6), 3beta-acetoxy-20alpha,21alpha-epoxytaraxastane (7)-were isolated from the aerial roots of Ficus microcarpa. Their structures were elucidated by spectroscopic and chemical methods.

Six new ursane- and oleanane-type triterpenes from the aerial roots of Ficus microcarpa

Four new ursane-type triterpenes, 3beta-acetoxy-11alpha-methoxy-12-ursene (1), 3beta-acetoxy-11alpha-ethoxy-12-ursene (2), 3beta-acetoxy-11alpha-hydroperoxy-12-ursene (3), 3beta-hydroxy-11alpha-hydroperoxy-12-ursene (4), and two new oleanane-type triterpenes, 3beta-acetoxy-11alpha-ethoxy-12-oleanene (5), 3beta-acetoxy-111alpha-hydroperoxy-12-oleanene (6), together with 3beta-acetoxy-11alpha-hydroxy-12-ursene (7), 3beta,11alpha-diacetoxy-12-ursene (8), 3beta-acetoxy-11alpha-hydroxy-12-oleanene (9), were isolated from the aerial roots of Ficus microcarpa L. f. Their structures were elucidated by spectroscopic and chemical methods.

Nonuniformity correction of infrared image sequences using the constant-statistics constraint

Using clues from neurobiological adaptation, we have developed the constant-statistics (CS) algorithm for nonuniformity correction of infrared focal point arrays (IRFPAs) and other imaging arrays. The CS model provides an efficient implementation that can also eliminate much of the ghosting artifact that plagues all scene-based nonuniformity correction (NUC) algorithms. The CS algorithm with deghosting is demonstrated on synthetic and real infrared (IR) sequences and shown to improve the overall accuracy of the correction procedure.

Development of chronic lymphocytic leukaemia in a case of Sjögren's syndrome with systemic lupus erythematosus

Persistent lymphocytosis and intermittent fever were found in a 68-yr-old Chinese woman 5 yr after the diagnosis of Sjögren's syndrome with systemic lupus erythematosus (SLE). A series of examinations--including virology, bone marrow aspiration and surface markers of lymphocytes--was made to evaluate the nature of the lymphocytosis which had not been found previously. All of the results were consistent with the diagnosis of B-cell chronic lymphocytic leukaemia (CLL). Development of CLL in Sjögren's syndrome has seldom been described before and may be added to other malignancies associated with Sjögren's syndrome.