Solid electrolyte, method for preparing the same, and battery using the same
A solid electrolyte including a composition represented by Formula 1 below is provided: aLi 2 O-bB 2 O 3 -cM-dX ( 1 ) wherein M is at least one selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 ; X is at least one selected from LiCl and Li 2 SO 4 ; 0.4<a<0.55; 0.4<b<0.55; 0.02<c<0.05; a+b+c=1, and 0≦d<0.2. A method for preparing the solid electrolyte and a battery using the solid electrolyte are also provided. The solid electrolyte exhibits high ionic conductivity. Lithium and thin film batteries using the solid electrolyte are improved in charge/discharge rate, power output, and cycle life.
1. A solid electrolyte comprising a composition represented by Formula 1 below:
aLi 2 O-bB 2 O 3 -cM-dX (1)
wherein M is at least one selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 ;
X is at least one selected from LiCl and Li 2 SO 4 ;
0.4<a<0.55; 0.4<b<0.55; 0.02<c<0.05; a+b+c=1, and 0≦d<0.2.
2. The solid electrolyte according to claim 1 , wherein a is in the range of 0.45 to 0.52, b is in the range of 0.45 to 0.52, c is in the range of 0.03 to 0.04, and d is in the range of 0.001 to 0.15.
3. A lithium battery using a solid electrolyte comprising a composition represented by Formula 1 below:
aLi 2 O-bB 2 O 3 -cM-dX (1)
wherein M is at least one selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 ;
X is at least one selected from LiCl and Li 2 SO 4 ;
0.4<a<0.55; 0.4<b<0.55; 0.02<c<0.05; a+b+c=1, and 0≦d<0.2.
4. A thin film battery using a solid electrolyte comprising a composition represented by Formula 1 below:
aLi 2 O-bB 2 O 3 -cM-dX (1)
wherein M is at least one selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 ;
X is at least one selected from LiCl and Li 2 SO 4 ;
0.4<a<0.55; 0.4<b<0.55; 0.02<c<0.05; a+b+c=1, and 0≦d<0.2.
5. A method for preparing a solid electrolyte comprising a composition represented by Formula 1 below:
aLi 2 O-bB 2 O 3 -cM-dX (1)
wherein M is at least one selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 ;
X is at least one selected from LiCl and Li 2 SO 4 ;
0.4<a<0.55; 0.4<b<0.55; 0.02<c<0.05; a+b+c=1, and 0≦d<0.2,
the method comprising:
(a) mixing a Li 2 O precursor compound; B 2 O 3 ; and at least one compound selected from the group consisting of TiO 2 , V 2 O 5 , WO 3 , and Ta 2 O 5 , followed by milling;
(b) heating the resultant powder mixture so that the Li 2 O precursor compound is thermally decomposed into Li 2 O;
(c) heating the resultant mixture to obtain a uniformly molten glass; and
(d) quenching the molten glass to obtain a glassy solid electrolyte.
6. The method according to claim 5 , further comprising adding at least one selected from LiCl and Li 2 SO 4 to the mixture of step (a).
7. The method according to claim 5 , wherein in step (b), Li 2 O is decomposed from the Li 2 O precursor compound at a temperature of 600 to 800° C.
8. The method according to claim 5 , wherein in step (c), the molten glass is obtained at a temperature of 900 to 1,500° C.
9. The method according to claim 5 , wherein in step (d), the molten glass is quenched at a temperature of 0 to 25° C.