People
Graduate Student
Rao Yifan
Title
PhD Student
Research Interests
Energy Storage
Research Group
Group Webpage
Office Location
S13-02-13
Selected Publications
- Rao, Yifan, Min Yuan, Bo Gao, Hui Li, Jiabing Yu, and Xianping Chen. “Laser-scribed phosphorus-doped graphene derived from Kevlar textile for enhanced wearable micro-supercapacitor.” Journal of Colloid and Interface Science 630, 586-594, 2023, ISSN: 0021-9797
- Rao, Yifan1, Min Yuan1, Feng Luo, Hui Li, Jiabing Yu, and Xianping Chen. “Laser In-Situ synthesis of metallic cobalt decorated porous graphene for flexible In-Plane microsupercapacitors.” Journal of Colloid and Interface Science 610, 775-784, 2022, ISSN: 0021-9797
- Rao, Yifan1, Min Yuan1, Feng Luo, Zeping Wang, Hui Li, Jiabing Yu, and Xianping Chen “One-step laser fabrication of phosphorus-doped porous graphene electrodes for high-performance flexible microsupercapacitor.” Carbon 180, 56-66, 2021. ISSN: 0008-6223.
I-FIM Publications:
2025 |
Lai, Wenhui; Lee, Jong Hak; Yeo, Zhen Yuan; Yuan, Yue; Liu, Yuqing; Shi, Lu; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos Maria Alava; Rao, Yifan; Xiong, Ting; Lanza, Mario; Loh, Duane N; Ozyilmaz, Barbaros Robust Silicon-Based Anode with High Energy Density upon Dual Welding Encapsulation ACS NANO, 19 (43), pp. 38040-38052, 2025, DOI: 10.1021/acsnano.5c13278. @article{WOS:001598368000001, title = {Robust Silicon-Based Anode with High Energy Density upon Dual Welding Encapsulation}, author = {Wenhui Lai and Jong Hak Lee and Zhen Yuan Yeo and Yue Yuan and Yuqing Liu and Lu Shi and Yanhui Pu and Yong Kang Ong and Carlos Maria Alava Limpo and Yifan Rao and Ting Xiong and Mario Lanza and Duane N Loh and Barbaros Ozyilmaz}, doi = {10.1021/acsnano.5c13278}, times_cited = {2}, issn = {1936-0851}, year = {2025}, date = {2025-11-01}, journal = {ACS NANO}, volume = {19}, number = {43}, pages = {38040-38052}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Silicon has long been considered one of the most promising anode materials for high-performance lithium-ion batteries due to its high theoretical capacity. However, a significant challenge that restricts its practical application is the persistent issue of weak interfacial contact in the silicon anode, which leads to structural instability during lithiation/delithiation processes due to large volume expansion. In this work, we develop a dual welding encapsulation strategy by constructing Si-C chemical bonding between the silicon and conductive covering shells and establishing C-C interlayer bonding connections among the covering shells. By directly examining the interface of silicon-based composites, we identify the types of compounds and hybrid orbital structures from their spatial distribution using machine-learning-enhanced transmission electron microscopy analysis techniques. This dual welding mechanism not only enhances the mechanical strength of the protective carbon shell but also ensures sustained electrical connection between the core and shell through the Si-C bonds. The robust heterogeneous structure effectively mitigates interfacial instability within the silicon anode, suppressing volume expansion below 12% after 300 cycles. Thus, the full-cell with the composite anode and LiNi0.8Co0.1Mn0.1O2 cathode performs a high energy density of 576 Wh kg-1 and stable cycling, inspiring the construction of commercial silicon batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Silicon has long been considered one of the most promising anode materials for high-performance lithium-ion batteries due to its high theoretical capacity. However, a significant challenge that restricts its practical application is the persistent issue of weak interfacial contact in the silicon anode, which leads to structural instability during lithiation/delithiation processes due to large volume expansion. In this work, we develop a dual welding encapsulation strategy by constructing Si-C chemical bonding between the silicon and conductive covering shells and establishing C-C interlayer bonding connections among the covering shells. By directly examining the interface of silicon-based composites, we identify the types of compounds and hybrid orbital structures from their spatial distribution using machine-learning-enhanced transmission electron microscopy analysis techniques. This dual welding mechanism not only enhances the mechanical strength of the protective carbon shell but also ensures sustained electrical connection between the core and shell through the Si-C bonds. The robust heterogeneous structure effectively mitigates interfacial instability within the silicon anode, suppressing volume expansion below 12% after 300 cycles. Thus, the full-cell with the composite anode and LiNi0.8Co0.1Mn0.1O2 cathode performs a high energy density of 576 Wh kg-1 and stable cycling, inspiring the construction of commercial silicon batteries.
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Lai, Wenhui; Lee, Jong Hak; Yuan, Yue; Ong, Yong Kang; Limpo, Carlos; Shi, Lu; Pu, Yanhui; Rao, Yifan; Lanza, Mario; Ozyilmaz, Barbaros Adjustable SiC interfacial layers toward reliable Si-based anode applications NANOSCALE HORIZONS, 10 (11), pp. 2931-2944, 2025, DOI: 10.1039/d5nh00338e. @article{WOS:001552275100001, title = {Adjustable SiC interfacial layers toward reliable Si-based anode applications}, author = {Wenhui Lai and Jong Hak Lee and Yue Yuan and Yong Kang Ong and Carlos Limpo and Lu Shi and Yanhui Pu and Yifan Rao and Mario Lanza and Barbaros Ozyilmaz}, doi = {10.1039/d5nh00338e}, times_cited = {3}, issn = {2055-6756}, year = {2025}, date = {2025-10-01}, journal = {NANOSCALE HORIZONS}, volume = {10}, number = {11}, pages = {2931-2944}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {The incorporation of a SiC interfacial layer has been recognized as an effective strategy to tackle the interface contact issue between Si and carbon, ensuring the structural integrity of Si-based anodes and thereby enhancing their cycling stability. However, its inherent low activity and poor conductivity pose a persistent challenge for maximizing capacity and facilitating ion and electron transport. Here, we present a thickness/content adjustable SiC interfacial layer in the Si-SiC-C heterostructure using a modified spark plasma sintering technique. The SiC layer, with a content of similar to 10%, is discretely coated on the surface of the Si core, exerting minimal influence on capacity and ion/electron kinetics, while ensuring high electrode structural stability. Consequently, the Si-based anode exhibits a stable capacity of 582 mAh g-1 (0.1 A g-1) and good rate capability (324 mAh g-1 at 2 A g-1), while maintaining 80% capacity retention over 500 cycles with a low electrode swelling of 12.6%. More importantly, its capacity presents a continuous rising trend with the increase of the cycle number, suggesting a mechanism where the SiC interfacial layer gradually transforms into a Li-ion-rich phase. This transformation facilitates ion transport and reaction with Si, resulting in gradual capacity enhancement. Therefore, the reasonably thickness-regulated SiC interfacial layer holds promise for providing inspiration for the design of commercial Si-based anodes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The incorporation of a SiC interfacial layer has been recognized as an effective strategy to tackle the interface contact issue between Si and carbon, ensuring the structural integrity of Si-based anodes and thereby enhancing their cycling stability. However, its inherent low activity and poor conductivity pose a persistent challenge for maximizing capacity and facilitating ion and electron transport. Here, we present a thickness/content adjustable SiC interfacial layer in the Si-SiC-C heterostructure using a modified spark plasma sintering technique. The SiC layer, with a content of similar to 10%, is discretely coated on the surface of the Si core, exerting minimal influence on capacity and ion/electron kinetics, while ensuring high electrode structural stability. Consequently, the Si-based anode exhibits a stable capacity of 582 mAh g-1 (0.1 A g-1) and good rate capability (324 mAh g-1 at 2 A g-1), while maintaining 80% capacity retention over 500 cycles with a low electrode swelling of 12.6%. More importantly, its capacity presents a continuous rising trend with the increase of the cycle number, suggesting a mechanism where the SiC interfacial layer gradually transforms into a Li-ion-rich phase. This transformation facilitates ion transport and reaction with Si, resulting in gradual capacity enhancement. Therefore, the reasonably thickness-regulated SiC interfacial layer holds promise for providing inspiration for the design of commercial Si-based anodes.
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Rao, Yifan; Lee, Jong Hak; Pu, Yanhui; Ong, Yong Kang; Shi, Lu; Lai, Wenhui; Limpo, Carlos; Yuan, Yue; Xiong, Ting; Lanza, Mario; Ozyilmaz, Barbaros Reinforcement-free monolithic all-in-one structural supercapacitors CHEMICAL ENGINEERING JOURNAL, 519 , 2025, DOI: 10.1016/j.cej.2025.165492. @article{WOS:001532082000001, title = {Reinforcement-free monolithic all-in-one structural supercapacitors}, author = {Yifan Rao and Jong Hak Lee and Yanhui Pu and Yong Kang Ong and Lu Shi and Wenhui Lai and Carlos Limpo and Yue Yuan and Ting Xiong and Mario Lanza and Barbaros Ozyilmaz}, doi = {10.1016/j.cej.2025.165492}, times_cited = {0}, issn = {1385-8947}, year = {2025}, date = {2025-09-01}, journal = {CHEMICAL ENGINEERING JOURNAL}, volume = {519}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {Structural supercapacitors, potential game-changers for various applications such as aerospace, automotive, and construction industries, offer a combination of energy storage and load-bearing functionalities. Conventional approaches, however, have been hindered by a significant decrease in overall energy storage performance due to the inherent separation of energy storage components and structural reinforcement elements. In this study, we report reinforcement-free all-in-one structural supercapacitors that tailor the conventional trade-off problem between energy capacity and mechanical strength by ensuring that the essential energy storage components possess high mechanical properties. This dual-functional structure ensures that it volumetrically constitutes nearly 90% of the cells excluding the packaging. Simultaneously, by employing interlocking interfacial engineering, we optimize the functionalities of these components, enhancing the overall robustness and energy capacity of the device. Consequently, our structural supercapacitor demonstrates good structural integrity, as evidenced by its flexural modulus of 8.34 GPa. Moreover, our supercapacitor stands out in terms of energy storage capacity, boasting a volumetric energy density of 45 Wh/L. This achievement, outperforming the current state-of-the-art by a staggering tenfold, significantly enhances multifunctionality, a critical index for evaluating structural energy devices, reaching a 9.95 rating. This novel strategy provides insight for other structural energy storage devices with higher multifunctional efficiency.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Structural supercapacitors, potential game-changers for various applications such as aerospace, automotive, and construction industries, offer a combination of energy storage and load-bearing functionalities. Conventional approaches, however, have been hindered by a significant decrease in overall energy storage performance due to the inherent separation of energy storage components and structural reinforcement elements. In this study, we report reinforcement-free all-in-one structural supercapacitors that tailor the conventional trade-off problem between energy capacity and mechanical strength by ensuring that the essential energy storage components possess high mechanical properties. This dual-functional structure ensures that it volumetrically constitutes nearly 90% of the cells excluding the packaging. Simultaneously, by employing interlocking interfacial engineering, we optimize the functionalities of these components, enhancing the overall robustness and energy capacity of the device. Consequently, our structural supercapacitor demonstrates good structural integrity, as evidenced by its flexural modulus of 8.34 GPa. Moreover, our supercapacitor stands out in terms of energy storage capacity, boasting a volumetric energy density of 45 Wh/L. This achievement, outperforming the current state-of-the-art by a staggering tenfold, significantly enhances multifunctionality, a critical index for evaluating structural energy devices, reaching a 9.95 rating. This novel strategy provides insight for other structural energy storage devices with higher multifunctional efficiency.
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2024 |
Lai, Wenhui; Lee, Jong Hak; Shi, Lu; Liu, Yuqing; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos; Xiong, Ting; Rao, Yifan; Sow, Chorng Haur; Ozyilmaz, Barbaros High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries 27 JOURNAL OF ENERGY CHEMISTRY, 93 , pp. 253-263, 2024, DOI: 10.1016/j.jechem.2024.02.021. @article{WOS:001203104900001, title = {High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries}, author = {Wenhui Lai and Jong Hak Lee and Lu Shi and Yuqing Liu and Yanhui Pu and Yong Kang Ong and Carlos Limpo and Ting Xiong and Yifan Rao and Chorng Haur Sow and Barbaros Ozyilmaz}, doi = {10.1016/j.jechem.2024.02.021}, times_cited = {27}, issn = {2095-4956}, year = {2024}, date = {2024-06-01}, journal = {JOURNAL OF ENERGY CHEMISTRY}, volume = {93}, pages = {253-263}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.
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Xiong, Ting; Zhang, Deqiang; Yeo, Jing Ying; Zhan, Yufeng; Ong, Yong Kang; Limpo, Carlos Maria Alava; Shi, Lu; Rao, Yifan; Pu, Yanhui; Lai, Wenhui; Lee, Jonghak; Lee, Wee Siang Vincent; Ozyilmaz, Barbaros Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density 14 JOURNAL OF MATERIALS CHEMISTRY A, 12 (9), pp. 5499-5507, 2024, DOI: 10.1039/d3ta07674a. @article{WOS:001156660000001, title = {Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density}, author = {Ting Xiong and Deqiang Zhang and Jing Ying Yeo and Yufeng Zhan and Yong Kang Ong and Carlos Maria Alava Limpo and Lu Shi and Yifan Rao and Yanhui Pu and Wenhui Lai and Jonghak Lee and Wee Siang Vincent Lee and Barbaros Ozyilmaz}, doi = {10.1039/d3ta07674a}, times_cited = {14}, issn = {2050-7488}, year = {2024}, date = {2024-02-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY A}, volume = {12}, number = {9}, pages = {5499-5507}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries. Graphene and positively polarized P(VDF-TrFE) assist in controlling Zn nucleation and growth on a Cu substrate, enabling high-performance zinc metal-free zinc-ion batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries. Graphene and positively polarized P(VDF-TrFE) assist in controlling Zn nucleation and growth on a Cu substrate, enabling high-performance zinc metal-free zinc-ion batteries.
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