10.1016/j.electacta.2014.04.084
Significant influence of insufficient lithium on electrochemical performance of lithium-rich layered oxide cathodes for lithium ion batteries

Li[Li1/3-2x/3Mn2/3-x/3Nix]O2 (x = 0.3) was prepared in two steps: formation of transition-metal hydroxide (Ni0.35Mn0.65(OH)2) and subsequent solid phase reaction of Ni0.35Mn0.75(OH)2 and Li2CO3. Specially, 8.74 g MnSO4*H2O (99%) and 7.20 g NiSO4*6H2O (98%) were dissolved into 400 ml H2O under magnetic stirring, and 10 ml ammonia hydroxide was then added as chelating agent. After being kept at 60 degC for 10 min, 100 ml aqueous solution containing 6.4 g KOH (98%) was slowly dropped, and the precipitation reaction was kept for 24 h. The resulting precipitation was mixed completely with lithium carbonate (98%). In this mixing, the precursors with 10 wt% excess lithium (E10), 5 wt% excess lithium (E5), stoichiometric lithium (ST), and 5 wt% deficient lithium (D5) were used. Four samples were obtained by calcining the mixture at 900 degC for 12 h, denoted as 900E10, 900E5, 900ST, and 900D5, respectively.
MnSO4*H2O
dissolved
8.74 g
g
MnSO4*H2O
99%
%
NiSO4*6H2O
dissolved
7.20 g
g
H2O
400 ml
ml
NiSO4*6H2O
98%
%
ammonia hydroxide
added
10 ml
ml
aqueous solution containing 6.4 g KOH (98%)
slowly dropped
100 ml
ml
100 ml aqueous solution
KOH (98%)
6.4 g
g
KOH
98%
%
precipitation reaction
kept
24 h
h
60 degC
degC
10 min
min
lithium carbonate
mixed
98%
%
precursors
excess lithium
10 wt%
wt%
precursors
excess lithium
5 wt%
wt%
precursors
deficient lithium
5 wt%
wt%
mixture
calcining
900 degC
degC
mixture
calcining
12 h
h