The disclosure relates to cerium based particles having a rough surface and their use as a component of a polishing composition, especially for chemical mechanical polishing. The cerium based particles have substantially the shape of polyhedrons which have one or more faces with protrusions thereon, said protrusions being integrally formed with said cerium based particles. The present disclosure also relates to the method of preparation of the cerium based particles.

Provided are a cobalt-free positive electrode material for a lithium ion battery, a preparation method therefor and a lithium ion battery. The method for preparing the cobalt-free positive electrode material for the lithium ion battery comprises: mixing lithium nickel manganese oxide with sulfate, so as to obtain a first mixture; and reacting the first mixture at a predetermined temperature, so as to obtain the cobalt-free positive electrode material. The cobalt-free positive electrode material comprises lithium nickel manganese oxide and a cladding layer of an outer surface thereof, and the cladding layer comprises lithium sulphate. The lithium ion battery comprises the cobalt-free positive electrode material. The cobalt-free positive electrode material has a relatively high electrical performance and a relatively low alkali content.

A zinc ion battery includes a cathode; an anode; a separator; and an electrolyte sandwiched between the cathode and the anode. The electrolyte includes a mixture of zinc perchlorate and sodium perchlorate, and a ratio of the sodium perchlorate to zinc perchlorate is at least 30.

A lithium metal composite oxide having a layered structure, including at least lithium and an element X, wherein:the element X is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S and P; the lithium metal composite oxide contains single particles and satisfies all of requirements (1) to (5):(1): a volume-based 50% cumulative particle size D.sub.50 of the lithium metal composite oxide is 2 μm or more and 10 μm or less; (2): the single particles have, on at least a part of surfaces thereof, adhered fine particles, with the proviso that a maximum particle size of the adhered fine particles is smaller than a particle size of the single particles; (3): the particle size of the single particles is 0.2 to 1.5 times D.sub.50 of the lithium metal composite oxide; (4): a particle size of the adhered fine particles is 0.01 to 0.1 times the D.sub.50 of the lithium metal composite oxide; and (5): an average number of the adhered fine particles adhered per particle of the single particles is 1 or more and 30 or less as measured with respect to a range observable in an image obtained by scanning electron microscope.

Provided are a positive electrode active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery including the same.

According to an exemplary embodiment, a positive electrode active material for a lithium secondary battery which includes lithium metal oxide particles and a coating layer placed on at least a part of a surface of the lithium metal oxide particles may be provided, wherein the coating layer includes B, LiOH, Li.sub.2CO.sub.3, and Li.sub.2SO.sub.4.

The present exemplary embodiments relate to a positive electrode active material and a lithium secondary battery including the same. The positive active material for a lithium secondary battery according to an exemplary embodiment includes lithium metal oxide particles including lithium, nickel, cobalt, manganese and doping elements, and includes a first domain and a second domain inside the lithium metal oxide particles.

A secondary battery with favorable cycle performance is provided. Alternatively, a secondary battery with higher capacity is provided. A positive electrode active material layer including a first graphene layer, a second graphene layer, and a positive electrode active material. The first graphene layer includes a first region covering the positive electrode active material. The second graphene layer includes a second region covering the positive electrode active material and a third region overlapping with the first region. The first region includes a plane positioned between the positive electrode active material and the third region and formed of arranged six-membered carbon rings. The positive electrode active material includes a fourth region with a layered rock-salt structure. A lithium layer with a layered rock-salt structure included in the fourth region is substantially perpendicular to the plane formed of six-membered carbon rings and included in the second region.

Provided are a hierarchical porous ZSM-5 molecular sieve and a preparation method therefor. The molecular sieve comprises micropores and mesopores, wherein the pore size of the micropores is 0.5-1.8 nm, the pore size of the mesopores is 4-30 nm, and the particle size is 0.3-4 μm. The molecular sieve is prepared by using a hemicellulose as a hard template agent. Also provided are a hierarchical porous HZSM-5 molecular sieve, which is obtained by subjecting the ZSM-5 molecular sieve to ion exchange with an ammonium chloride solution, and the use of ZSM-5 and HZSM-5 molecular sieves in the preparation of a sound-absorbing material, the sound-absorbing material made from the molecular sieve, and a speaker loaded with the sound-absorbing material. After being prepared into sound-absorbing particles, the molecular sieve can more effectively improve the absorption and desorption performances of air molecules, improve the low-frequency response of a speaker, improve the acoustic performance of the speaker, and improve the acoustic improvement stability of sound-absorbing particles in the speaker.

Provided are enhanced MXene materials made from MAX-phase precursors that comprise an excess of metal A. The resultant enhanced MXenes exhibit improved stability over periods of days and months, particularly when stored in aqueous media.

There is provided a method for collecting and reusing an active material from positive electrode scrap. The positive electrode active material reuse method of the present disclosure includes (a) thermally treating positive electrode scrap comprising an active material layer on a current collector in air for thermal decomposition of a binder and a conductive material in the active material layer, to separate the current collector from the active material layer, and collecting an active material in the active material layer, (b) washing the collected active material using a lithium precursor aqueous solution which is basic in an aqueous solution and drying, and (c) annealing the washed active material to obtain a reusable active material.