Negative electrode active material having improved output characteristics and electrode for electrochemical device including the negative electrode active material
The present disclosure relates to a negative electrode active material having excellent output characteristics and causing little gas generation, and an electrode including the negative electrode active material. The negative electrode active material includes metal oxide-lithium titanium oxide (MO-LTO) composite particles which have a shape of secondary particles formed by aggregation of primary particles, wherein the primary particles have a core-shell structure including a core and a shell totally or at least partially covering the surface of the core, the core includes primary particles of lithium titanium oxide (LTO), and the shell includes a metal oxide.
1. A negative electrode for an electrochemical device which comprises:
a current collector; and
an electrode active material layer formed on at least one surface of the current collector,
wherein the electrode active material layer comprises a metal oxide-lithium titanium oxide (MO-LTO) composite particles which have a shape of secondary particles formed by aggregation of primary particles, wherein the primary particles have a core-shell structure comprising a core and a shell totally or at least partially covering a surface of the core, the core comprises primary particles of lithium titanium oxide (LTO), and the shell comprises a metal oxide,
wherein the shell is an outer layer of the primary particles, and
wherein the electrode active material layer comprises the MO-LTO composite particles and a content of the secondary particles thereof is 80 wt% or more.
2. The negative electrode for an electrochemical device according to claim 1 , wherein the primary particles of lithium titanium oxide (LTO) has a chemical composition represented by the following Chemical Formula 1:
Li x Ti y O z M w [Chemical Formula 1]
Wherein M is any one selected from the group consisting of Zr, B, Sn, S, Be, Ge and Zn, or a combination of two or more of them, 0.5≤x≤3, 1≤y≤5, 2≤z≤12, and 0≤w<0.1.
3. The negative electrode for an electrochemical device according to claim 1 , wherein the metal oxide is an oxide of a metal selected from the group consisting of Al, Zr, B, Li and Ti.
4. The negative electrode for an electrochemical device according to claim 1 , wherein the metal oxide is at least one selected from the group consisting of Al 2 O 3 and ZrO 2 .
5. The negative electrode for an electrochemical device according to claim 1 , wherein the primary particles have a D 50 (volume-based density distribution) of 0.1-1 μm.
6. The negative electrode for an electrochemical device according to claim 1 , wherein the secondary particles have a D 50 (volume-based density distribution) of 2-50 μm.
7. An electrochemical device which comprises a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode and an electrolyte, wherein the negative electrode is defined in claim 1 .
8. The electrochemical device according to claim 7 , which is a lithium ion secondary battery or a hybrid super capacitor.