Energy storage device based on nanocrystals including metal oxide rescaled by lithiation and supercapacitor using the same
Disclosed is an energy storage device based on metal oxide nanocrystals resealed through lithiation, and a supercapacitor using the same. The energy storage device is fabricated by dispersing transition metal nanoparticles over a carbon-based support with a large specific surface area, and then, dispersing and resealing the nanoparticles over the support using lithium ions with strong reductive ability, so that the resealed metal particles are substantially particles dispersed and resealed over the support as particles having a size of less than 1 nanometer on the scale of atomic units. The supercapacitor is fabricated using the energy storage device. The energy storage device higher capacitance than before resealing of metal oxide. Since the resealed metal particles are those having a size of less than 1 nanometer on the scale of atomic units, interference between particles disappears to exhibit excellent cycle life characteristics of 100% maintained performance in even more than 100,000 cycles.
1. An energy storage device based on atomic clusters including transition metal oxide rescaled by lithiation, comprising: a carbon support; and transition metal nanoparticles dispersed thereon to be rescaled on the support by intercalation/deintercalation of lithium ions, wherein divalent transition metal ion (M 2 +) of the transition metal nanoparticles is reversely changed to zero-valent transition metal state (M 0 ) during lithiation and delithiation, and wherein the divalent transition metal ion reacts with atomic unit scale oxygen by lithiation, and is maintained on the scale of the atomic units when a duster returns to the transition metal oxide state while removing lithium in a M:LiO x core-shell structure,
wherein the transition metal oxide is at least one selected from RuO 2 , IrO 2 , MnO 2 , Mn 3 O 4 , Co 3 O 4 , NiCo 2 O 4 , V 2 O 5 , SnO 2 , TiO 2 , MoO 3 , and Fe 2 O 3 .
2. The device according to claim 1 , wherein the carbon is at least one selected from graphene, carbon nanotube and activated carbon.
3. The device according to claim 1 , wherein the transition metal particle has a size of 0.6 to 1 nanometer.
4. A supercapacitor with high current density of 12 A/g and long term cycle of 100,000 or more characteristics fabricated using the energy storage device based on nanocrystals including the rescaled transition metal oxide according to claim 1 .