Identifying degradation patterns of lithium ion batteries from impedance spectroscopy using machine learning.

Forecasting the state of health and remaining useful life of Li-ion batteries is an unsolved challenge that limits technologies such as consumer electronics and electric vehicles. Here, we build an accurate battery forecasting system by combining electrochemical impedance spectroscopy (EIS)-a real-time, non-invasive and information-rich measurement that is hitherto underused in battery diagnosis-with Gaussian process machine learning. Over 20,000 EIS spectra of commercial Li-ion batteries are collected at different states of health, states of charge and temperatures-the largest dataset to our knowledge of its kind.

Publisher's Note: Direct Imaging of Dynamic Glassy Behavior in a Strained Manganite Film [Phys. Rev. Lett. 115, 265701 (2015)].

This corrects the article DOI: 10.1103/PhysRevLett.115.

Direct Imaging of Dynamic Glassy Behavior in a Strained Manganite Film.

Complex many-body interaction in perovskite manganites gives rise to a strong competition between ferromagnetic metallic and charge-ordered phases with nanoscale electronic inhomogeneity and glassy behaviors. Investigating this glassy state requires high-resolution imaging techniques with sufficient sensitivity and stability. Here, we present the results of a near-field microwave microscope imaging on the strain-driven glassy state in a manganite film.

Repulsively driven frequency-increased-generators for durable energy harvesting from ultra-low frequency vibration.

An electromagnetic kinetic energy harvester has been developed, which can convert ultra-low-frequency motion and vibration energy into electrical power. This harvester employs a two-stage vibratory structure to collect low-frequency kinetic energy and effectively transfer it into electric power by using a pair of high-frequency resonant generators. Non-contact magnetic repulsive force is herein utilized for the 1st-stage sliding vibrator to drive the 2nd-stage resonators into frequency-up-conversion resonance.