Flakelike LiCoO₂ with Exposed {010} Facets As a Stable Cathode Material for Highly Reversible Lithium Storage

Abstract

A thick and dense flakelike LiCoO2 with exposed {010} active facets is synthesized using Co(OH)2 nanoflake as a self-sacrificial template obtained from a simple coprecipitation method, and served as a cathode material for lithium ion batteries. When operated at a high cutoff voltage up to 4.5 V, the resultant LiCoO2 exhibits an outstanding rate capability, delivering a reversible discharge capacity as high as 179, 176, 168, 116, and 96 mA h g(-1) at 25 °C under the current rate of 0.1, 0.5, 1, 5, and 10 C, respectively. When charge/discharge cycling at 55 °C, a high specific capacity of 148 mA h g(-1) (∼88% retention) can be retained after 100 cycles under 1 C, demonstrating excellent cycling and thermal stability. Besides, the flakelike LiCoO2 also shows an impressive low-temperature electrochemical activity with specific capacities of 175 (0.1 C) and 154 mA h g(-1) (1 C) at -10 °C, being the highest ever reported for a subzero-temperature lithium storage capability, as well as 52% capacity retention even after 80 cycles under 1 C. Such superior high-voltage electrochemical performances of the flakelike LiCoO2 operated at a wide temperature range are mainly attributed to its unique hierarchical structure with specifically exposed facets. The exposed {010} active facets provide a preferential crystallographic orientation for Li-ion migration, while the micrometer-sized secondary particles agglomerated by submicron primary LiCoO2 flakes endow the electrode with better structural integrity, both of which ensure the LiCoO2 cathode to manifest remarkably enhanced reversible lithium storage properties.

Nanostructured Electrode Materials for Rechargeable Lithium-Ion Batteries

“…Moreover, because Co is expensive and toxic, LiCoO 2 has a high cost, and environmental safety is a concern. For instance, flakelike LiCoO 2 with exposed {010} active facets were synthesized through a facile co-precipitation method and served as a cathode material for LIBs [161]. When operating at a high cutoff voltage of 4.5 V, the resultant LiCoO 2 delivered a reversible discharge capacity of 179, 176, 168, 116, and 96 mAh g -1 at 25 o C under the current rate of 0.1, 0.5, 1, 5, and 10C, respectively.…”

Sputtering TiO2 on LiCoO2 composite electrodes as a simple and effective coating to enhance high-voltage cathode performance

“…Compared with other known materials, LiCoO 2 also has the largest true density (5.2 g cm -3 ), which is a highly weighted factor in particular for small-format power units. Although LiCoO 2 has been studied for tens of years, the efforts to further improving its performance has never stopped and the exploration of its high-voltage limit becomes increasing active in recent years [2][3][4][5][6][7]. Theoretically, it is still possible to further increase the capacity of LiCoO 2 by elevating its charging potential above the normal limit of 4.25 V vs. Li/Li + in order to push up its energy density.…”

Restoration of Degraded Nickel‐Rich Cathode Materials for Long‐Life Lithium‐Ion Batteries

“…The D Li of TNCA is about 2.6 times than that of DNCA. It follows then that the reduced R f and R ct for TNCA is a composite consequence of the reduction of the side reaction caused by the elimination of the lithium impurities and the increase of both the electronic conductivity and the Li ion diffusion coefficient …”