Abstract: According to one embodiment, a memory system includes a nonvolatile memory and a controller electrically connected to the nonvolatile memory. The controller selects a write mode from a first mode in which data having N bits is written per one memory cell and a second mode in which data having M bits is written per one memory cell. N is equal to or larger than one. M is larger than N. The controller writes data into the nonvolatile memory in the selected write mode. The controller selects either the first mode or the second mode at least based on a total number of logical addresses mapped in a physical address space of the nonvolatile memory.

Abstract: A memory system includes a nonvolatile memory; and a controller configured to (i) select one of a plurality of read retry processes having different average required times, respectively, based on reliability of a target area of the nonvolatile memory on which a read process is to be executed and (ii) execute the selected read retry process.

Abstract: According to one embodiment, a memory system includes a nonvolatile memory and a controller electrically connected to the nonvolatile memory. The controller selects a write mode from a first mode in which data having N bits is written per one memory cell and a second mode in which data having M bits is written per one memory cell. N is equal to or larger than one. M is larger than N. The controller writes data into the nonvolatile memory in the selected write mode. The controller selects either the first mode or the second mode at least based on a total number of logical addresses mapped in a physical address space of the nonvolatile memory.

Abstract: According to an embodiment, a memory system includes a nonvolatile memory and a memory controller. The nonvolatile memory includes a first memory cell configured to nonvolatilely store data of a plurality of bits including a first bit and a second bit, and a second memory cell configured to nonvolatilely store data of at least one bit. The memory controller is configured to execute a save operation in accordance with reception of a command from a host, in the save operation, write first bit data to the second memory cell in a case where the first memory cell stores the first bit data as the first bit and does not store data as the second bit, and transmit, to the host, a completion response to the command after the first bit data has been written to the second memory cell.

Abstract: According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory includes blocks each containing memory cells. The controller is configured to instruct the semiconductor memory to execute a first operation and a second operation. In the first operation and the second operation, the semiconductor memory selects at least one of the blocks, and applies at least one voltage to all memory cells contained in said selected blocks. A number of blocks to which said voltage is applied per unit time in the second operation is larger than that in the first operation.

Abstract: An organic sulfur material comprising carbon, hydrogen, oxygen, and sulfur as constituent elements, and having peaks in the vicinity of 482 cm?1, 846 cm?1, 1066 cm?1, 1279 cm?1, and 1442 cm?1 in a Raman spectrum detected by Raman spectroscopy, the peak in the vicinity of 1442 cm?1 being most intense, has a high capacity and high heat resistance, although a liquid organic starting material is used.

Abstract: An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

Abstract: The present invention provides an organic sulfur material comprising carbon, hydrogen, and sulfur as constituent elements, and having peaks in the vicinity of 480 cm?1, 1250 cm?1, 1440 cm?1, and 1900 cm?1 in a Raman spectrum detected by Raman spectroscopy. The peak in the vicinity of 1440 cm?1 is the most intense peak. This organic sulfur material, which is produced by using a liquid organic starting material, achieves high capacity. This organic sulfur material preferably does not have peaks in the vicinity of 846 cm?1 or 1066 cm?1.

Abstract: An object of the present invention is to provide a novel positive electrode which is produced using a rubber being an inexpensive material and is capable of enhancing a charge and discharge capacity and cyclability of a lithium-ion secondary battery, and the lithium-ion secondary battery composed of the positive electrode. In the lithium-ion secondary battery, the positive electrode comprises a current collector and an electrode layer formed on a surface of the current collector, the electrode layer comprises an active material, an electrically-conductive additive and a thermosetting resin binder subjected to thermosetting, and the active material comprises a sulfur-based positive-electrode active material prepared by heat-treating a starting material comprising a rubber and sulfur under a non-oxidizing atmosphere.

Abstract: An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

Abstract: An object of the present invention is to provide a novel positive electrode which is produced using a rubber being an inexpensive material and is capable of enhancing a charge and discharge capacity and cyclability of a lithium-ion secondary battery, and the lithium-ion secondary battery composed of the positive electrode. In the lithium-ion secondary battery, the positive electrode comprises a current collector and an electrode layer formed on a surface of the current collector, the electrode layer comprises an active material, an electrically-conductive additive and a thermosetting resin binder subjected to thermosetting, and the active material comprises a sulfur-based positive-electrode active material prepared by heat-treating a starting material comprising a rubber and sulfur under a non-oxidizing atmosphere.

Abstract: An object of the present invention is to provide a positive-electrode active material comprising a carbon-sulfur structure which has Raman shift peaks at around 500 cm?1, at around 1,250 cm?1 and at around 1,450 cm?1 in a Raman spectrum, and by using the positive-electrode active material, it is possible to greatly improve cycling characteristics of a lithium-ion secondary battery.

Abstract: The present invention provides an organic sulfur material comprising carbon, hydrogen, and sulfur as constituent elements, and having peaks in the vicinity of 480 cm?1, 1250 cm?1, 1440 cm?1, and 1900 cm?1 in a Raman spectrum detected by Raman spectroscopy. The peak in the vicinity of 1440 cm?1 is the most intense peak. This organic sulfur material, which is produced by using a liquid organic starting material, achieves high capacity. This organic sulfur material preferably does not have peaks in the vicinity of 846 cm?1 or 1066 cm?1.

Abstract: An organic sulfur material comprising carbon, hydrogen, oxygen, and sulfur as constituent elements, and having peaks in the vicinity of 482 cm?1, 846 cm?1, 1066 cm?1, 1279 cm?1, and 1442 cm?1 in a Raman spectrum detected by Raman spectroscopy, the peak in the vicinity of 1442 cm?1 being most intense, has a high capacity and high heat resistance, although a liquid organic starting material is used.

Abstract: To provide a lithium ion secondary battery capable of suppressing thermal run-away when internal short circuiting occurs. The lithium ion secondary battery includes: a positive electrode including a current collector, a positive electrode active material layer that is formed on the current collector and that contains a lithium-containing complex oxide having a layered rock salt structure and being represented by general formula: LiaNibCocMndDeOf (0.2?a?1; b+c+d+e=1; 0?e<1; D is at least one element selected from Li, Fe, Cr, Cu, Zn, Ca, Mg, S, Si, Na, K, and Al; 1.7?f?2.1), and a thermal run-away suppressing layer formed on the positive electrode active material layer and containing a lithium transition metal silicate; and a negative electrode including a negative electrode active material. A ratio of the mass of the lithium-containing complex oxide with respect to the mass of the lithium transition metal silicate in the positive electrode is not lower than 1.5.

Abstract: An object of the present invention is to provide a novel positive electrode which is produced using a rubber being an inexpensive material and is capable of enhancing a charge and discharge capacity and cyclability of a lithium-ion secondary battery, and the lithium-ion secondary battery composed of the positive electrode. In the lithium-ion secondary battery, the positive electrode comprises a current collector and an electrode layer formed on a surface of the current collector, the electrode layer comprises an active material, an electrically-conductive additive and a thermosetting resin binder subjected to thermosetting, and the active material comprises a sulfur-based positive-electrode active material prepared by heat-treating a starting material comprising a rubber and sulfur under a non-oxidizing atmosphere.

Abstract: A lithium-ion secondary battery of the present invention comprises a positive electrode including a positive electrode active material composite formed by compositing a lithium silicate-based material and a carbon material, a negative electrode including a negative electrode active material containing a silicon, and an electrolyte. The lithium-ion secondary battery satisfies 0.8<B/A<1.2, where A is irreversible capacity of the positive electrode and B is irreversible capacity of the negative electrode.

Abstract: An object of the present invention is to provide a novel sulfur-based positive-electrode active material which can largely improve cyclability of a lithium-ion secondary battery, a positive electrode comprising the positive-electrode active material and a lithium-ion secondary battery comprising the positive electrode. The sulfur-based positive-electrode active material is one comprising: a carbon skeleton derived from a polymer composed of a monomer unit having at least one hetero atom-containing moiety, and sulfur incorporated into the carbon skeleton as the carbon skeleton is formed from the polymer by heat treatment.

Abstract: Provided are a positive electrode active material for a sodium ion secondary battery, and a positive electrode and a sodium ion secondary battery using the material. The positive electrode active material for a sodium ion secondary battery comprises a lithium sodium-based compound containing lithium (Li), sodium (Na), iron (Fe), and oxygen (O).

Abstract: An object of the present invention is to provide a positive-electrode active material comprising a carbon-sulfur structure which has Raman shift peaks at around 500 cm?1, at around 1,250 cm?1 and at around 1,450 cm?1 in a Raman spectrum, and by using the positive-electrode active material, it is possible to greatly improve cycling characteristics of a lithium-ion secondary battery.