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Jiaqi Wei

Bio: Jiaqi Wei is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Materials science & Electrolyte. The author has an hindex of 15, co-authored 20 publications receiving 1729 citations.

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Journal ArticleDOI
TL;DR: A stirring hydrothermal process that enables the formation of elongated bending TiO2 -based nanotubes is presented, which can cycle over 10 000 times in half cells while retaining a relatively high capacity.
Abstract: A stirring hydrothermal process that enables the formation of elongated bending TiO2 -based nanotubes is presented. By making use of its bending nature, the elongated TiO2 (B) nanotubular crosslinked-network anode electrode can cycle over 10 000 times in half cells while retaining a relatively high capacity (114 mA h g(-1)) at an ultra-high rate of 25 C (8.4 A g(-1)).

390 citations

Journal ArticleDOI
TL;DR: Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, Stretchable, and wearable devices.
Abstract: Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device-level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO2 nanowire composites are developed. A supercapacitor edited with honeycomb-like structure shows a specific capacitance of 227.2 mF cm-2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state-of-the-art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch-and-release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices.

284 citations

Journal ArticleDOI
TL;DR: In this article, a sublimation-induced synthesis of phosphorus-based composite nanosheets by a chemistry-based solvothermal reaction is reported for high performance lithium-ion battery (LIB) applications due to their high theoretical specific capacity.
Abstract: Phosphorus-based materials are promising for high-performance lithium-ion battery (LIB) applications due to their high theoretical specific capacity. Currently, the existing physical methods render great difficulty toward rational engineering on the nanostructural phosphorus or its composites, thus limiting its high-rate LIB applications. For the first time, a sublimation-induced synthesis of phosphorus-based composite nanosheets by a chemistry-based solvothermal reaction is reported. Its formation mechanism involves solid–vapor–solid transformation driven by continuous vaporization–condensation process, as well as subsequent bottom-up assembly growth. The proof-of-concept LIBs composed of the phosphorus-based nanosheets achieve a high capacity of 630 mAh g−1 at an ultrahigh current density of 20 A g−1, which is attributed to efficient lithium-ion diffusion and electron transfer. Such simple sublimation-induced transformation opens up new prospects for rational engineering of phosphorus-based materials for enhancing electrochemical performance.

193 citations

Journal ArticleDOI
TL;DR: The stirring hydrothermal method was used to control the aspect ratio of viscous titanate nanotubes, which were used to fabricate additive-free TiO2 -based electrode materials, and it was found that the battery performance at high charging/discharging rates is dramatically boosted when the aspects ratio is increased.
Abstract: The fundamental understanding of the relationship between the nanostructure of an electrode and its electrochemical performance is crucial for achieving high-performance lithium-ion batteries (LIBs). In this work, the relationship between the nanotubular aspect ratio and electrochemical performance of LIBs is elucidated for the first time. The stirring hydrothermal method was used to control the aspect ratio of viscous titanate nanotubes, which were used to fabricate additive-free TiO2-based electrode materials. We found that the battery performance at high charging/discharging rates is dramatically boosted when the aspect ratio is increased, due to the optimization of electronic/ionic transport properties within the electrode materials. The proof-of-concept LIBs comprising nanotubes with an aspect ratio of 265 can retain more than 86 % of their initial capacity over 6000 cycles at a high rate of 30 C. Such devices with supercapacitor-like rate performance and battery-like capacity herald a new paradigm for energy storage systems.

173 citations

Journal ArticleDOI
TL;DR: Solution-processable inks based on lithium titanate with a conductive network architecture, toward high-rate lithium-ion batteries (LIBs) with a customized configuration are developed and are compatible for on-demand coating techniques.
Abstract: Solution-processable inks based on lithium titanate with a conductive network architecture, toward high-rate lithium-ion batteries (LIBs) with a customized configuration are developed. The inks, with tunable viscosity, are compatible for on-demand coating techniques. The lithium titanate electrode derived from these inks exhibits excellent high-rate capacity (≈124 mA h g(-1) at 90 C, 15.7 A g(-1) ) after 1000 cycles.

169 citations


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TL;DR: The two-step solution-phase reactions to form hybrid materials of Mn(3)O(4) nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications should offer a new technique for the design and synthesis of battery electrodes based on highly insulating materials.
Abstract: We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

1,587 citations

Journal ArticleDOI
TL;DR: In this article, a review of recent advances in supercapacitor (SC) technology with respect to charge storage mechanisms, electrode materials, electrolytes (e.g., particularly paper/fiber-like 3D porous structures), and their practical applications is presented.

1,058 citations

Journal ArticleDOI
TL;DR: In this article, the fundamental electrochemical properties of pseudocapacitive materials, with emphasis on kinetic processes and distinctions between battery and pseudo-capacitive material, are described.
Abstract: Batteries and supercapacitors serve as the basis for electrochemical energy-storage devices. Although both rely on electrochemical processes, their charge-storage mechanisms are dissimilar, giving rise to different energy and power densities. Pseudocapacitive materials store charge through battery-like redox reactions but at fast rates comparable to those of electrochemical double-layer capacitors; these materials, therefore, offer a pathway for achieving both high energy and high power densities. Materials that combine these properties are in demand for the realization of fast-charging electrochemical energy-storage devices capable of delivering high power for long periods of time. In this Review, we describe the fundamental electrochemical properties of pseudocapacitive materials, with emphasis on kinetic processes and distinctions between battery and pseudocapacitive materials. In addition, we discuss the various types of pseudocapacitive materials, highlighting the differences between intrinsic and extrinsic materials; assess device applications; and consider the future prospects for the field. Pseudocapacitive materials can bridge the gap between high-energy-density battery materials and high-power-density electrochemical capacitor materials. In this Review, we examine the electrochemistry and physical signatures of pseudocapacitive charge-storage processes and discuss existing pseudocapacitive materials.

952 citations

Journal ArticleDOI
TL;DR: This tutorial review presents the state-of-the-art developments in ultrafast charging LIBs by the rational design of materials, and several aspects of the intrinsic materials, materials engineering and processing, and electrode materials architecture design towards maximizing both ionic and electronic conductivity in the electrode with a short diffusion length.
Abstract: Rechargeable lithium-ion batteries (LIBs) are important electrochemical energy storage devices for consumer electronics and emerging electrical/hybrid vehicles. However, one of the formidable challenges is to develop ultrafast charging LIBs with the rate capability at least one order of magnitude (>10 C) higher than that of the currently commercialized LIBs. This tutorial review presents the state-of-the-art developments in ultrafast charging LIBs by the rational design of materials. First of all, fundamental electrochemistry and related ionic/electronic conduction theories identify that the rate capability of LIBs is kinetically limited by the sluggish solid-state diffusion process in electrode materials. Then, several aspects of the intrinsic materials, materials engineering and processing, and electrode materials architecture design towards maximizing both ionic and electronic conductivity in the electrode with a short diffusion length are deliberated. Finally, the future trends and perspectives for the ultrafast rechargeable LIBs are discussed. Continuous rapid progress in this area is essential and urgent to endow LIBs with ultrafast charging capability to meet huge demands in the near future.

804 citations

Journal ArticleDOI
TL;DR: In this article, the crystal structure of 1D TiO2 and the latest development on the fabrication of 2D and 3D 1DTiO2 nanostructured materials are reviewed.
Abstract: One-dimensional TiO2 (1D TiO2) nanomaterials with unique structural and functional properties have been extensively used in various fields including photocatalytic degradation of pollutants, photocatalytic CO2 reduction into energy fuels, water splitting, solar cells, supercapacitors and lithium-ion batteries. In the past few decades, 1D TiO2 nanostructured materials with a well-controlled size and morphology have been designed and synthesized. Compared to 0D and 2D nanostructures, more attention has been paid to 1D TiO2 nanostructures due to their high aspect ratio, large specific surface area, and excellent electronic or ionic charge transport properties. In this review, we present the crystal structure of TiO2 and the latest development on the fabrication of 1D TiO2 nanostructured materials. Besides, we will look into some critical engineering strategies that give rise to the excellent properties of 1D TiO2 nanostructures such as improved enlargement of the surface area, light absorption and efficient separation of electrons/holes that benefit their potential applications. Moreover, their corresponding environmental and energy applications are described and discussed. With the fast development of the current economy and technology, more and more effort will be put into endowing TiO2-based materials with advanced functionalities and other promising applications.

757 citations