Lithium doping of cobalt-nickel spinel oxides at low temperatures
- Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of General and Inorganic Chemistry
Cobalt-nickel spinel oxides containing lithium (Li{sub y}(Ni{sub x}Co{sub 1{minus}x}){sub 3{minus}y}O{sub 4}, y {approx} 0.13, 0 {le} x {le} 0.4) are prepared by thermal decomposition of mixed cobalt-nickel hydroxide-nitrates with a double-chain structure, Ni{sub x}Co{sub 1{minus}x}(OH)(NO{sub 3}){center_dot}H{sub 2}O in a lithium nitrate medium. XRD analysis, DTA and magnetic susceptibility measurements show that double-chain Ni{sub x}Co{sub 1{minus}x}(OH)(NO{sub 3}){center_dot}H{sub 2}O 0 < x < 0.4 decomposes to nickel-cobalt spinels via layered hydroxide-nitrates Ni{sub x}Co{sub 1{minus}x}(OH){sub 1.5}(NO{sub 3}){sub 0.5}, but in a LiNO{sub 3} medium, lithium containing nickel-cobalt spinels Li{sub y}(Ni{sub x}Co{sub 1{minus}x}){sub 3{minus}y}O{sub 4} are obtained, preceded by a complete oxidative hydrolysis of double-chain Ni{sub x}Co{sub 1{minus}x}(OH)(NO{sub 3}){center_dot}H{sub 2}O to layered oxide-hydroxides Ni{sub x}Co{sub 1{minus}x}OOH in a LiNO{sub 3} melt. With increasing nickel content (0.4 < x < 1), the thermal decomposition of the coprecipitated cobalt-nickel hydroxide-nitrates in a lithium nitrate medium leads to the formation of two phases consisting of Li{sub y}(Ni{sub x}Co{sub 1{minus}x}){sub 3{minus}y}O{sub 4} (y {approx} 0.13, x {approx} 0.4) spinels and a rock-salt Ni{sub 1{minus}b}Co{sub b}O (b {le} 0.1), the relative amount of the latter increasing with the nickel content in the precursor mixture. Low-temperature lithium doping of NiO can not be achieved with this preparation procedure since Ni(OH)(NO{sub 3}){center_dot}H{sub 2}O hydrolyzes only to a layered nickel hydroxide-nitrate Ni(OH){sub 1.5}(NO{sub 3}){sub 0.5} in a lithium nitrate medium.
- OSTI ID:
- 271752
- Journal Information:
- Materials Research Bulletin, Vol. 31, Issue 6; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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