A positive electrode active material includes a lithium transition metal oxide having a nickel content of 70 mol % or greater with respect to all metals excluding lithium, wherein EELS analysis results for a particle surface satisfy Equation 1 below:

0.85I(854 eV)/I(855.5 eV)<1[Equation 1] wherein I (854 eV) indicates a peak intensity observed around 854 eV, and I (855.5 eV) indicates a peak intensity observed around 855.5 eV.

Recovered carbon black (rCB) comprising carbon black, inorganic ash and carbon-based residues resulting from the decomposition of pneumatic rubbers and/or elastomer residues, characterized in that said content of carbon-based residues, determined with respect to the percentage of area of the C.sub.1 peak measured by X-ray photoelectron spectroscopy, is less than or equal to 1% of said area of the C.sub.1 peak, said percentage of area of the C.sub.1 peak being calculated with respect to the total area of the C.sub.0 to C.sub.5 peaks.

A gallium-containing nitride crystals are disclosed, comprising: a top surface having a crystallographic orientation within about 5 degrees of a plane selected from a (0001) +c-plane and a (000-1) c-plane; a substantially wurtzite structure; n-type electronic properties; an impurity concentration of hydrogen greater than about 510.sup.17 cm.sup.3; an impurity concentration of oxygen between about 210.sup.17 cm.sup.3 and about 110.sup.20 cm.sup.3; an [H]/[O] ratio of at least 0.3; an impurity concentration of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl greater than about 110.sup.16 cm.sup.3; a compensation ratio between about 1.0 and about 4.0; an absorbance per unit thickness of at least 0.01 cm.sup.1 at wavenumbers of approximately 3175 cm.sup.1, 3164 cm.sup.1, and 3150 cm.sup.1; and wherein, at wavenumbers between about 3200 cm.sup.1 and about 3400 cm.sup.1 and between about 3075 cm.sup.1 and about 3125 cm.sup.1, said gallium-containing nitride crystal is essentially free of infrared absorption peaks having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3175 cm.