Limits...
Controlled synthesis of series NixCo3-xO4 products: Morphological evolution towards quasi-single-crystal structure for high-performance and stable lithium-ion batteries.

Zhou Y, Liu Y, Zhao W, Wang H, Li B, Zhou X, Shen H - Sci Rep (2015)

Bottom Line: At the current density of 0.8 A g(-1), it can deliver a high discharge capacities of 1470 mAh g(-1) over 100 cycles (105% of the 2nd cycle) and 590 mAh g(-1) even after 1000 cycles.To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of Ni(x)Co(3-x)O4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized.The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China.

ABSTRACT
Transition metal oxides are very promising alternative anode materials for high-performance lithium-ion batteries (LIBs). However, their conversion reactions and concomitant volume expansion cause the pulverization, leading to poor cycling stability, which limit their applications. Here, we present the quasi-single-crystal Ni(x)Co(3-x)O4 hexagonal microtube (QNHM) composed of continuously twinned single crystal submicron-cubes as anode materials for LIBs with high energy density and long cycle life. At the current density of 0.8 A g(-1), it can deliver a high discharge capacities of 1470 mAh g(-1) over 100 cycles (105% of the 2nd cycle) and 590 mAh g(-1) even after 1000 cycles. To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of Ni(x)Co(3-x)O4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized. The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization. It is important to note that such quasi-single-crystal structure would be helpful to explore other high-energy lithium storage materials based on alloying or conversion reactions.

No MeSH data available.


Related in: MedlinePlus

Electrochemical performances of LIBs based on QNHMs, square microtubes, and circular microtubes.Galvanostatic charge-discharge curves of (a) QNHMs, (b) square microtubes, and (c) circular microtubes cycled at the 1st, 2nd, 50th and 100th between 3 and 0.01 V (vs Li/Li+) at a current density of 0.8 A g−1. (d) The cycling performance of QNHMs, square microtubes, and circular microtubes at a current density of 0.8 A g−1. (e) Rate capability of QNHMs, square microtubes, and circular microtubes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4478471&req=5

f5: Electrochemical performances of LIBs based on QNHMs, square microtubes, and circular microtubes.Galvanostatic charge-discharge curves of (a) QNHMs, (b) square microtubes, and (c) circular microtubes cycled at the 1st, 2nd, 50th and 100th between 3 and 0.01 V (vs Li/Li+) at a current density of 0.8 A g−1. (d) The cycling performance of QNHMs, square microtubes, and circular microtubes at a current density of 0.8 A g−1. (e) Rate capability of QNHMs, square microtubes, and circular microtubes.

Mentions: Figure 5a–c show the selected discharge and charge profiles of the electrodes at a current density of 0.8 A g−1 over the potential range of 0.01–3.0 V. The first discharge capacities of QNHM electrode was 2218 mAh g−1, which was much larger than those of square microtube electrode (1903 mAh g−1) and circular microtube electrode (1276 mAh g−1). After the second cycle, QNHM electrode also presented much better electrochemical lithium storage performance and cycling stability than others. For instance, the discharge capacities of QNHM electrode were 1399 mAh g−1, 1442 mAh g−1, and 1470 mAh g−1 in the 2nd, 50th, 100th cycle, respectively. In contrast, the discharge capacities decreased to 1187 mAh g−1 for square microtube and 794 mAh g−1 for circular microtube after 2nd cycle, and then quickly dropped to 652 mAh g−1 for square microtube and 615 mAh g−1 for circular microtube in 100th cycle. The cycle performance of electrodes was further investigated at a current density of 0.8 A g−1 and obviously QNHM electrode demonstrated the best cycle stability (Fig. 5d). Surprisingly, even after 1000 cycles, the QNHM electrode still retained a discharge capacity of 590 mAh g−1. In addition, the QNHM electrode showed enhanced rate capacity in comparison with square microtube and circular microtube electrodes (Fig. 5e). The QNHM electrode could deliver high discharge capacity of 1400, 1300, 1200, 1150, 1100 mAh g−1 when the current density changed stepwise from 0.8 to 1.6, 2.4, 3.2, and 4.0 A g−1, respectively. More importantly, after this high-rate charge-discharge process, a stable capacity of 1350 mA g−1 could be supplied again when the current rate was reduced back to 0.8 A g−1, indicating great potential as the high rate electrode materials. It should be noted that the capacities of QNHMs reported here are higher than the theoretical value (890 mAh g−1), which was generally observed in the transitional metal oxide electrode studies614363738. As discussed in previous literatures, the extra capacity is attributed to “pseudo-capacitive behavior”, which originates from the reversible formation/decomposition of polymergic/gel-like film on the surface of active materials during the discharge/charge processes15394041. Meanwhile, the large excess capacities of QNHMs were reversible and well preserved during long-term discharge/charge cycles. According to the observation and detail discussion in following paragraph, QNHMs can retain good structural integrity upon cycling that is favorable for the ease and access of ions and electrons in the Li2O/Co matrix. The discharge capacity retention and cycling stability for QNHMs reported here are higher than that of previously reported Co3O4 or NixO3-xO4 electrodes with exposed specific crystal planes6, high surface area81415, one dimensional structures9101112131617, and even that treated with graphene supports181920214243 while tested under similar conditions. To the best of our knowledge, this is the first time the successful synthesis of quasi-single-crystal NixCo3-xO4 structure and maybe one of the best performances among NixCo3-xO4 based LIBs.


Controlled synthesis of series NixCo3-xO4 products: Morphological evolution towards quasi-single-crystal structure for high-performance and stable lithium-ion batteries.

Zhou Y, Liu Y, Zhao W, Wang H, Li B, Zhou X, Shen H - Sci Rep (2015)

Electrochemical performances of LIBs based on QNHMs, square microtubes, and circular microtubes.Galvanostatic charge-discharge curves of (a) QNHMs, (b) square microtubes, and (c) circular microtubes cycled at the 1st, 2nd, 50th and 100th between 3 and 0.01 V (vs Li/Li+) at a current density of 0.8 A g−1. (d) The cycling performance of QNHMs, square microtubes, and circular microtubes at a current density of 0.8 A g−1. (e) Rate capability of QNHMs, square microtubes, and circular microtubes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4478471&req=5

f5: Electrochemical performances of LIBs based on QNHMs, square microtubes, and circular microtubes.Galvanostatic charge-discharge curves of (a) QNHMs, (b) square microtubes, and (c) circular microtubes cycled at the 1st, 2nd, 50th and 100th between 3 and 0.01 V (vs Li/Li+) at a current density of 0.8 A g−1. (d) The cycling performance of QNHMs, square microtubes, and circular microtubes at a current density of 0.8 A g−1. (e) Rate capability of QNHMs, square microtubes, and circular microtubes.
Mentions: Figure 5a–c show the selected discharge and charge profiles of the electrodes at a current density of 0.8 A g−1 over the potential range of 0.01–3.0 V. The first discharge capacities of QNHM electrode was 2218 mAh g−1, which was much larger than those of square microtube electrode (1903 mAh g−1) and circular microtube electrode (1276 mAh g−1). After the second cycle, QNHM electrode also presented much better electrochemical lithium storage performance and cycling stability than others. For instance, the discharge capacities of QNHM electrode were 1399 mAh g−1, 1442 mAh g−1, and 1470 mAh g−1 in the 2nd, 50th, 100th cycle, respectively. In contrast, the discharge capacities decreased to 1187 mAh g−1 for square microtube and 794 mAh g−1 for circular microtube after 2nd cycle, and then quickly dropped to 652 mAh g−1 for square microtube and 615 mAh g−1 for circular microtube in 100th cycle. The cycle performance of electrodes was further investigated at a current density of 0.8 A g−1 and obviously QNHM electrode demonstrated the best cycle stability (Fig. 5d). Surprisingly, even after 1000 cycles, the QNHM electrode still retained a discharge capacity of 590 mAh g−1. In addition, the QNHM electrode showed enhanced rate capacity in comparison with square microtube and circular microtube electrodes (Fig. 5e). The QNHM electrode could deliver high discharge capacity of 1400, 1300, 1200, 1150, 1100 mAh g−1 when the current density changed stepwise from 0.8 to 1.6, 2.4, 3.2, and 4.0 A g−1, respectively. More importantly, after this high-rate charge-discharge process, a stable capacity of 1350 mA g−1 could be supplied again when the current rate was reduced back to 0.8 A g−1, indicating great potential as the high rate electrode materials. It should be noted that the capacities of QNHMs reported here are higher than the theoretical value (890 mAh g−1), which was generally observed in the transitional metal oxide electrode studies614363738. As discussed in previous literatures, the extra capacity is attributed to “pseudo-capacitive behavior”, which originates from the reversible formation/decomposition of polymergic/gel-like film on the surface of active materials during the discharge/charge processes15394041. Meanwhile, the large excess capacities of QNHMs were reversible and well preserved during long-term discharge/charge cycles. According to the observation and detail discussion in following paragraph, QNHMs can retain good structural integrity upon cycling that is favorable for the ease and access of ions and electrons in the Li2O/Co matrix. The discharge capacity retention and cycling stability for QNHMs reported here are higher than that of previously reported Co3O4 or NixO3-xO4 electrodes with exposed specific crystal planes6, high surface area81415, one dimensional structures9101112131617, and even that treated with graphene supports181920214243 while tested under similar conditions. To the best of our knowledge, this is the first time the successful synthesis of quasi-single-crystal NixCo3-xO4 structure and maybe one of the best performances among NixCo3-xO4 based LIBs.

Bottom Line: At the current density of 0.8 A g(-1), it can deliver a high discharge capacities of 1470 mAh g(-1) over 100 cycles (105% of the 2nd cycle) and 590 mAh g(-1) even after 1000 cycles.To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of Ni(x)Co(3-x)O4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized.The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization.

View Article: PubMed Central - PubMed

Affiliation: School of Physics and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China.

ABSTRACT
Transition metal oxides are very promising alternative anode materials for high-performance lithium-ion batteries (LIBs). However, their conversion reactions and concomitant volume expansion cause the pulverization, leading to poor cycling stability, which limit their applications. Here, we present the quasi-single-crystal Ni(x)Co(3-x)O4 hexagonal microtube (QNHM) composed of continuously twinned single crystal submicron-cubes as anode materials for LIBs with high energy density and long cycle life. At the current density of 0.8 A g(-1), it can deliver a high discharge capacities of 1470 mAh g(-1) over 100 cycles (105% of the 2nd cycle) and 590 mAh g(-1) even after 1000 cycles. To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of Ni(x)Co(3-x)O4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized. The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization. It is important to note that such quasi-single-crystal structure would be helpful to explore other high-energy lithium storage materials based on alloying or conversion reactions.

No MeSH data available.


Related in: MedlinePlus