Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries
In this project, monoclinic Li3V2(PO4)3 (LVP) nanocrystals embedded in a nanoporous carbon matrix attached to reduced graphene oxide (rGO) nanosheets (LVP-NC@NPCM@rGO) are synthesized by a sol-gel method using NH4VO3, CH3COOLi∙2H2O, NH4H2PO4, citric acid and graphene oxide (GO) as starting materials...
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| Format: | Final Year Project (FYP) |
| Language: | English |
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2012
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| Online Access: | http://hdl.handle.net/10356/48409 |
| _version_ | 1824455369760440320 |
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| author | Wong, Kang Ming. |
| author2 | School of Materials Science and Engineering |
| author_facet | School of Materials Science and Engineering Wong, Kang Ming. |
| author_sort | Wong, Kang Ming. |
| collection | NTU |
| description | In this project, monoclinic Li3V2(PO4)3 (LVP) nanocrystals embedded in a nanoporous carbon matrix attached to reduced graphene oxide (rGO) nanosheets (LVP-NC@NPCM@rGO) are synthesized by a sol-gel method using NH4VO3, CH3COOLi∙2H2O, NH4H2PO4, citric acid and graphene oxide (GO) as starting materials. The structure and morphology of the samples were characterized by FESEM, TEM, XRD, Raman spectroscopy, TGA and nitrogen adsorption-desorption isotherms. The results reveal that 20-80 nm nanoparticles, consisting of 5-8 nm monoclinic LVP nanocrystals, embedded in a nanoporous carbon matrix with pore sizes of around 4 nm and attached to rGO nanosheets are successfully synthesized. In addition, the LVP-NC@NPCM@rGO exhibits high specific surface area which allowed it to be further fabricated into binder-free cathodes.
The electrochemical measurements show that the LVP-NC@NPCM@rGO cathode displays excellent Li storage capabilities. In the voltage window of 3 to 4.3 V and at a current density of 66 mA g-1 (0.5 C), this cathode depicts an initial discharge capacity of 128 mAh g-1 (theoretical: 130 mAh g-1) and also displays excellent cycling stabilities with almost no capacity fading when subjected to 100 cycles of charging and discharging. In addition, even at high current density of 6600 mA g-1 (50 C), it is still able to deliver a constant discharge capacity of 88 mAh g-1 for 1000 cycles. In the voltage window of 3 to 4.8 V and at a current density of 40 mA g-1 (0.2 C), the cathode exhibits an even higher initial charge capacity of 181 mAh g-1, contributed by the extraction of the third Li+ at 4.6 V, which gradually decreases to 164 mAh g-1 during the 100th cycle and this is better than the performance that was ever reported for LVP-based cathodes. On top of that, the cathode is able to display excellent cycling performance and deliver a discharge capacity of 91 mAh g-1 during the 1000th cycle even at high current density of 5910 mAh g-1 (30 C).
Lastly, the reasons for the excellent electrochemical performance of the LVP-NC@NPCM@rGO cathode and the purposed formation scheme of hierarchical LVP-NC@NPCM@rGO nanoarchitectures are also discussed in the report. |
| first_indexed | 2025-02-19T03:37:07Z |
| format | Final Year Project (FYP) |
| id | ntu-10356/48409 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T03:37:07Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | ntu-10356/484092023-03-04T15:36:58Z Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries Wong, Kang Ming. School of Materials Science and Engineering Yan Qingyu DRNTU::Engineering::Materials::Nanostructured materials In this project, monoclinic Li3V2(PO4)3 (LVP) nanocrystals embedded in a nanoporous carbon matrix attached to reduced graphene oxide (rGO) nanosheets (LVP-NC@NPCM@rGO) are synthesized by a sol-gel method using NH4VO3, CH3COOLi∙2H2O, NH4H2PO4, citric acid and graphene oxide (GO) as starting materials. The structure and morphology of the samples were characterized by FESEM, TEM, XRD, Raman spectroscopy, TGA and nitrogen adsorption-desorption isotherms. The results reveal that 20-80 nm nanoparticles, consisting of 5-8 nm monoclinic LVP nanocrystals, embedded in a nanoporous carbon matrix with pore sizes of around 4 nm and attached to rGO nanosheets are successfully synthesized. In addition, the LVP-NC@NPCM@rGO exhibits high specific surface area which allowed it to be further fabricated into binder-free cathodes. The electrochemical measurements show that the LVP-NC@NPCM@rGO cathode displays excellent Li storage capabilities. In the voltage window of 3 to 4.3 V and at a current density of 66 mA g-1 (0.5 C), this cathode depicts an initial discharge capacity of 128 mAh g-1 (theoretical: 130 mAh g-1) and also displays excellent cycling stabilities with almost no capacity fading when subjected to 100 cycles of charging and discharging. In addition, even at high current density of 6600 mA g-1 (50 C), it is still able to deliver a constant discharge capacity of 88 mAh g-1 for 1000 cycles. In the voltage window of 3 to 4.8 V and at a current density of 40 mA g-1 (0.2 C), the cathode exhibits an even higher initial charge capacity of 181 mAh g-1, contributed by the extraction of the third Li+ at 4.6 V, which gradually decreases to 164 mAh g-1 during the 100th cycle and this is better than the performance that was ever reported for LVP-based cathodes. On top of that, the cathode is able to display excellent cycling performance and deliver a discharge capacity of 91 mAh g-1 during the 1000th cycle even at high current density of 5910 mAh g-1 (30 C). Lastly, the reasons for the excellent electrochemical performance of the LVP-NC@NPCM@rGO cathode and the purposed formation scheme of hierarchical LVP-NC@NPCM@rGO nanoarchitectures are also discussed in the report. Bachelor of Engineering (Materials Engineering) 2012-04-17T06:41:24Z 2012-04-17T06:41:24Z 2012 2012 Final Year Project (FYP) http://hdl.handle.net/10356/48409 en Nanyang Technological University 49 p. application/pdf |
| spellingShingle | DRNTU::Engineering::Materials::Nanostructured materials Wong, Kang Ming. Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title | Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title_full | Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title_fullStr | Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title_full_unstemmed | Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title_short | Li3V2(PO4)3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium-ion batteries |
| title_sort | li3v2 po4 3 nanocrystals embedded in a nanoporous carbon matrix supported on reduced graphene oxide sheets as cathode material for lithium ion batteries |
| topic | DRNTU::Engineering::Materials::Nanostructured materials |
| url | http://hdl.handle.net/10356/48409 |
| work_keys_str_mv | AT wongkangming li3v2po43nanocrystalsembeddedinananoporouscarbonmatrixsupportedonreducedgrapheneoxidesheetsascathodematerialforlithiumionbatteries |