Lg Energy Solution, Ltd.

Other

Seoul National University

Hyo Jung Yoon

So Young Kim

Eun Ju Lee

Hakhyun Nam

Geun Sig Cha

Ji Yeon Kim

Jin Seo Lee

Jae Ho Shin

Dae Soo Kim

Gang Cui

Kyu Tae Lee

Young Deok Kim

Mi-Sook Kwon

Shin Gwon Lim

Su Won Jee

A method of diagnosing degradation of an electrode active material for a secondary battery including obtaining a first differential curve (dQ/dV) by differentiating an initial charge/discharge curve obtained by performing first charging and first discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, and obtaining a second differential curve (dQ/dV) by differentiating a charge/discharge curve obtained by performing second charging and second discharging of the lithium secondary battery in a voltage range of 2.5 V to 4.2 V, and diagnosing whether a beta phase of the positive electrode active material has been formed by comparing maximum discharge peak values of the first differential curve and the second differential curve.

Method of diagnosing degradation of electrode active material for lithium secondary battery

Provided is a method of diagnosing the degradation of a lithium secondary battery in a non-destructive manner without disassembling the battery, which includes: obtaining, from X-ray diffraction (XRD) data obtained during first charging of the lithium secondary battery, a first graph showing the change of the c-axis d-spacing value of the layered positive electrode active material according to the number of moles of lithium ions deintercalated from the layered positive electrode active material during the charging; obtaining, from XRD data obtained during second charging of the lithium secondary battery, a second graph showing the change of the c-axis d-spacing value of the layered positive electrode active material according to the number of moles of lithium ions deintercalated from the layered positive electrode active material during the charging; and classifying a cause of degradation of the secondary battery by comparing the first graph and the second graph.

Diagnosis of cause of degradation of lithium secondary battery

A positive electrode active material for a sodium secondary battery includes a sodium composite transition metal oxide represented by Formula 1 and having a P3 crystal structure, and a positive electrode and a sodium secondary battery which include the positive electrode active material.Na[LiM]O&#x2003;&#x2003;[Formula 1]wherein M is at least one transition metal, 0.64&#x2264;x&#x2264;0.7, and 0.01&#x2264;a&#x2264;0.1.

Method for producing sodium composite transition metal oxide, positive electrode active material for sodium secondary battery, positive electrode and sodium secondary battery comprising the same

The present invention relates to chloride-selective electrodes which comprise insoluble metal salt layer and a protecting membrane formed of hydrophilic polyurethane thereon, wherein the hydrophilic polyurethane coated chloride-selective electrodes show fast activation and response time and are usefully employed to accurately measure the chloride by reducing the interference from bromide and iodide or preventing the surface of the electrode from protein adsorption.

Hydrophilic polyurethane-coated chloride-selective electrodes

Growing community of inventors

Daejeon, South Korea

Hyo Jung Yoon