There is disclosed a method of making a surface-modified alkali metal material for electrochemical use, the method comprising bringing a barrier agent into frictional contact with an alkali metal substrate to form a tribochemical barrier layer on the substrate. Also disclosed is a surface-modified alkali metal material for electrochemical use, the material comprising an alkali metal substrate bearing a tribochemical barrier layer.

There is disclosed a method of making a surface-modified alkali metal material for electrochemical use, the method comprising bringing a barrier agent into frictional contact with an alkali metal substrate to form a tribochemical barrier layer on the substrate. Also disclosed is a surface-modified alkali metal material for electrochemical use, the material comprising an alkali metal substrate bearing a tribochemical barrier layer.

A negative electrode active material having a specific aspect ratio and sphericity in a cumulative particle volume distribution. When tested by using a dynamic particle image analyzer, when a cumulative particle volume distribution of the negative electrode active material is 10%, an aspect ratio AR.sub.10 of the negative electrode active material satisfies 0.4≤AR.sub.10≤0.55, and a sphericity S.sub.10 of the negative electrode active material satisfies 0.48≤S.sub.10≤0.60. The negative electrode active material improves rate performance, dynamics performance, and a deformation problem of the electrochemical apparatus.

The fabrication of single-crystalline ionically conductive materials and related articles and systems are generally described.

A negative electrode active material includes a carbon material, where the carbon material has a specific degree of graphitization and aspect ratio distribution. A degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92, and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is less than 10%. The negative electrode active material helps to improve cycle performance of the electrochemical apparatus. FIG. 1.

Secondary batteries using lithium cobalt oxide as positive electrode active materials have a problem of a decrease in battery capacity due to repeated charging/discharging, for example. A positive electrode active material particle which hardly deteriorates is provided. In a first step, a container in which a lithium oxide and a fluoride are set is placed in a heating furnace, and in a second step, the inside of the heating furnace is heated in an atmosphere containing oxygen. The heating temperature of the second step is from 750° C. to 950° C., inclusive. By the manufacturing method, fluorine can be contained in the positive electrode active material particle to increase the wettability of the surface of the positive electrode active material so that the surface of the positive electrode active material is homogenized and planarized. The crystal structure of the thus manufactured positive electrode active material is unlikely to be broken in repeated high-voltage charging/discharging. Thus, secondary batteries using the positive electrode active material having such a feature have greatly improved cycle characteristics.

There is provided a method of synthesizing a porous carbon-sulfur composite comprising the step of carbonizing a carbon material having a metal-organic framework (MOF) at a temperature of 800-1000° C. to produce a porous carbon, mixing and heating the porous carbon with sulfur to infuse the sulfur (melt diffusion) into the pores of the porous carbon and removing excess sulfur not infused into the pores or present on the surface of the porous carbon. There is also provided a cathode comprising the porous carbon-sulfur composite and a method of preparing the cathode by mixing with conductive carbon and a polymer binder. The cathode finds use in an electrochemical cell comprising a sodium or lithium anode.

The present invention is related to a manufacturing method of a negative active material for a lithium secondary battery, a negative active material for a lithium secondary battery manufactured by the method, and a lithium secondary battery including the same. According to one embodiment, it is provided that: a method of manufacturing a negative active material for lithium secondary battery, comprising: coating a negative active material precursor containing Si with crude tar or soft pitch; and annealing an obtained coating product, wherein, the crude tar contains a low molecular weight component that can be removed by a distillation process in an amount of 20 wt % or less.

A thickness meter detects a thickness of an electrode plate of a secondary battery at three or more points in a width direction of the electrode plate. A calculator calculates three feature amounts of a first deviation between the thickness target value and a thickness measurement value of a point closest to a first compression mechanism among the three or more points, a second deviation between the thickness target value and a thickness measurement value of a point closest to a second compression mechanism among the three or more points, and a secondary component of a thickness profile of the electrode plate from thickness measurement values at the three or more points and the thickness target value, and adaptively changes the setting values of the first compression mechanism, the second compression mechanism, a first bend mechanism, and a second bend mechanism on the basis of the three feature amounts.

A thickness meter detects a thickness of an electrode plate of a secondary battery at three or more points in a width direction of the electrode plate. A calculator calculates three feature amounts of a first deviation between the thickness target value and a thickness measurement value of a point closest to a first compression mechanism among the three or more points, a second deviation between the thickness target value and a thickness measurement value of a point closest to a second compression mechanism among the three or more points, and a secondary component of a thickness profile of the electrode plate from thickness measurement values at the three or more points and the thickness target value, and adaptively changes the setting values of the first compression mechanism, the second compression mechanism, a first bend mechanism, and a second bend mechanism on the basis of the three feature amounts.