A negative electrode material includes a composite of a silicon-based material (1), a polymer (2), and carbon nanotubes (3), where the polymer (2) contains a first group and a second group, the first group is chemically bonded to the carbon nanotubes (3), and the second group is chemically bonded to the silicon-based material (1). Both the carbon nanotubes (3) and the polymer (2) containing two groups are applied to surfaces of particles of the silicon-based material (1). The two groups of the polymer (2) are chemically bonded to the silicon-based material (1) and the carbon nanotubes (3) respectively, so that bonding force between the silicon-based material (1) and the carbon nanotubes (3) is enhanced and a uniform carbon nanotube (3) coating layer is formed. This can significantly improve conductive performance of the silicon-based material (1), thereby improving cycling performance and rate performance of an electrochemical apparatus.

A negative electrode material includes a composite of a silicon-based material (1), a polymer (2), and carbon nanotubes (3), where the polymer (2) contains a first group and a second group, the first group is chemically bonded to the carbon nanotubes (3), and the second group is chemically bonded to the silicon-based material (1). Both the carbon nanotubes (3) and the polymer (2) containing two groups are applied to surfaces of particles of the silicon-based material (1). The two groups of the polymer (2) are chemically bonded to the silicon-based material (1) and the carbon nanotubes (3) respectively, so that bonding force between the silicon-based material (1) and the carbon nanotubes (3) is enhanced and a uniform carbon nanotube (3) coating layer is formed. This can significantly improve conductive performance of the silicon-based material (1), thereby improving cycling performance and rate performance of an electrochemical apparatus.

According to the present disclosure, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, so as to contribute in improving the safety property of the secondary battery. The manufacturing method of the electrode plate herein disclosed includes a precursor preparing step for preparing an electrode precursor 20A including an active material provided area A1 in which an electrode active material layer 24 is provided on a surface of the electrode core 22 and including a core exposed area A2 in which the electrode active material layer 24 is not provided and the electrode core 22 is exposed, and an active material provided area cutting step for cutting the active material provided area A1 by a pulse laser, and a core exposed area cutting step for cutting the core exposed area A2 by the pulse laser. Then, in the case where the pulse width (ns) of the pulse laser is represented by X and the lap rate (%) is represented by Y for the core exposed area cutting step, a condition represented by Y≥−3log X+106 is satisfied. According to the manufacturing method of the electrode plate as described above, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, and thus it is possible to contribute in improving the safety property of the secondary battery.

According to the present disclosure, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, so as to contribute in improving the safety property of the secondary battery. The manufacturing method of the electrode plate herein disclosed includes a precursor preparing step for preparing an electrode precursor 20A including an active material provided area A1 in which an electrode active material layer 24 is provided on a surface of the electrode core 22 and including a core exposed area A2 in which the electrode active material layer 24 is not provided and the electrode core 22 is exposed, and an active material provided area cutting step for cutting the active material provided area A1 by a pulse laser, and a core exposed area cutting step for cutting the core exposed area A2 by the pulse laser. Then, in the case where the pulse width (ns) of the pulse laser is represented by X and the lap rate (%) is represented by Y for the core exposed area cutting step, a condition represented by Y≥−3log X+106 is satisfied. According to the manufacturing method of the electrode plate as described above, it is possible to inhibit the electrically conductive foreign substance from falling off and being peeled off from the electrode plate that has been already manufactured, and thus it is possible to contribute in improving the safety property of the secondary battery.

A positive electrode comprising a current collector and a positive electrode active material layer disposed on at least one surface of the current collector, and a lithium-sulfur battery comprising the positive electrode are provided. The positive electrode active material layer comprises a positive electrode active material and an additive, and the additive comprises a transition metal-ferrocyanide compound.

A positive electrode comprising a current collector and a positive electrode active material layer disposed on at least one surface of the current collector, and a lithium-sulfur battery comprising the positive electrode are provided. The positive electrode active material layer comprises a positive electrode active material and an additive, and the additive comprises a transition metal-ferrocyanide compound.

A negative electrode active material containing a negative electrode active material particle which includes a silicon compound particle containing a silicon compound (SiO.sub.x: 0.5≤x≤1.6). The silicon compound particle has three or more peaks in a chemical shift value ranging from −40 ppm to −120 ppm but has no peak in a chemical shift value within a range of −65±3 ppm in a spectrum obtained from .sup.29Si-MAS-NMR of the silicon compound particle. This provides a negative electrode active material capable of improving cycle characteristics when it is used as a negative electrode active material for a secondary battery.

A negative electrode active material containing a negative electrode active material particle which includes a silicon compound particle containing a silicon compound (SiO.sub.x: 0.5≤x≤1.6). The silicon compound particle has three or more peaks in a chemical shift value ranging from −40 ppm to −120 ppm but has no peak in a chemical shift value within a range of −65±3 ppm in a spectrum obtained from .sup.29Si-MAS-NMR of the silicon compound particle. This provides a negative electrode active material capable of improving cycle characteristics when it is used as a negative electrode active material for a secondary battery.

A composite containing phosphorus, lithium, iron, sulfur, and carbon as constituent elements wherein lithium sulfide (Li.sub.2S) is present in an amount of 90 mol % or more, and wherein the crystallite size calculated from the half-width of a diffraction peak based on the (111) plane of Li.sub.2S as determined by X-ray powder diffraction measurement is 80 nm or less. The composite exhibits a high capacity (in particular, a high discharge capacity) useful as an electrode active material for a lithium-ion secondary battery (in particular, a cathode active material for a lithium-ion secondary battery), without the need for stepwise pre-cycling treatment.

A composite containing phosphorus, lithium, iron, sulfur, and carbon as constituent elements wherein lithium sulfide (Li.sub.2S) is present in an amount of 90 mol % or more, and wherein the crystallite size calculated from the half-width of a diffraction peak based on the (111) plane of Li.sub.2S as determined by X-ray powder diffraction measurement is 80 nm or less. The composite exhibits a high capacity (in particular, a high discharge capacity) useful as an electrode active material for a lithium-ion secondary battery (in particular, a cathode active material for a lithium-ion secondary battery), without the need for stepwise pre-cycling treatment.