Jie Zeng

Bio: Jie Zeng is an academic researcher from Harbin Institute of Technology. The author has contributed to research in topics: Graphene & Supercapacitor. The author has an hindex of 7, co-authored 12 publications receiving 542 citations.

Weavable, Conductive Yarn-Based NiCo//Zn Textile Battery with High Energy Density and Rate Capability

Abstract: With intrinsic safety and much higher energy densities than supercapacitors, rechargeable nickel/cobalt–zinc-based textile batteries are promising power sources for next generation personalized wearable electronics. However, high-performance wearable nickel/cobalt–zinc-based batteries are rarely reported because there is a lack of industrially weavable and knittable highly conductive yarns. Here, we use scalably produced highly conductive yarns uniformly covered with zinc (as anode) and nickel cobalt hydroxide nanosheets (as cathode) to fabricate rechargeable yarn batteries. They possess a battery level capacity and energy density, as well as a supercapacitor level power density. They deliver high specific capacity of 5 mAh cm–3 and energy densities of 0.12 mWh cm–2 and 8 mWh cm–3 (based on the whole solid battery). They exhibit ultrahigh rate capabilities of 232 C (liquid electrolyte) and 116 C (solid electrolyte), which endows the batteries excellent power densities of 32.8 mW cm–2 and 2.2 W cm–3 (based...

Graphene/MoS2/FeCoNi(OH)x and Graphene/MoS2/FeCoNiPx multilayer-stacked vertical nanosheets on carbon fibers for highly efficient overall water splitting

Abstract: Development of excellent and cheap electrocatalysts for water electrolysis is of great significance for application of hydrogen energy. Here, we show a highly efficient and stable oxygen evolution reaction (OER) catalyst with multilayer-stacked hybrid structure, in which vertical graphene nanosheets (VGSs), MoS2 nanosheets, and layered FeCoNi hydroxides (FeCoNi(OH)x) are successively grown on carbon fibers (CF/VGSs/MoS2/FeCoNi(OH)x). The catalyst exhibits excellent OER performance with a low overpotential of 225 and 241 mV to attain 500 and 1000 mA cm−2 and small Tafel slope of 29.2 mV dec−1. Theoretical calculation indicates that compositing of FeCoNi(OH)x with MoS2 could generate favorable electronic structure and decrease the OER overpotential, promoting the electrocatalytic activity. An alkaline water electrolyzer is established using CF/VGSs/MoS2/FeCoNi(OH)x anode for overall water splitting, which generates a current density of 100 mA cm−2 at 1.59 V with excellent stability over 100 h. Our highly efficient catalysts have great prospect for water electrolysis. While water-splitting electrocatalysis offers a renewable means for carbon-neutral energy production, it is a challenge to design efficient, active, and stable catalysts. Here, authors prepare multilayer composite nanosheet materials as bifunctional water-splitting electrocatalysts.

3D Graphene Fibers Grown by Thermal Chemical Vapor Deposition

Abstract: 3D assembly of graphene sheets (GSs) is important for preserving the merits of the single-atomic-layered structure. Simultaneously, vertical growth of GSs has long been a challenge for thermal chemical vapor deposition (CVD). Here, vertical growth of the GSs is achieved in a thermal CVD reactor and a novel 3D graphene structure, 3D graphene fibers (3DGFs), is developed. The 3DGFs are prepared by carbonizing electrospun polyacrylonitrile fibers in NH3 and subsequently in situ growing the radially oriented GSs using thermal CVD. The GSs on the 3DGFs are densely arranged and interconnected with the edges fully exposed on the surface, resulting in high performances in multiple aspects such as electrical conductivity (3.4 × 104 -1.2 × 105 S m-1 ), electromagnetic shielding (60 932 dB cm2 g-1 ), and superhydrophobicity and superoleophilicity, which are far superior to the existing 3D graphene materials. With the extraordinary properties along with the easy scalability of the simple thermal CVD, the novel 3DGFs are highly promising for many applications such as high-strength and conducting composites, flexible conductors, electromagnetic shielding, energy storage, catalysis, and separation and purification. Furthermore, this strategy can be widely used to grow the vertical GSs on many other substrates by thermal CVD.

A flexible, electrochromic, rechargeable Zn//PPy battery with a short circuit chromatic warning function

Abstract: A rechargeable battery with both flexibility and electrochromism integrated into a single apparatus is a major component for smart flexible electronics. However, suitable electrode materials with electrochromic properties are still being searched for. Here, for the first time to the best of our knowledge, we realize a flexible, electrochromic and rechargeable battery by successfully matching electrochromic polypyrrole (PPy, as cathode) with zinc (Zn, as anode). The fabricated rechargeable Zn//PPy battery delivers a high capacity of 123 mA h gPPy−1. It possesses flexibility and an electrochromic capability of turning from black to yellow when the voltage changes from 1.2 to 0 V. Therefore, the battery exhibits a unique function of a short circuit chromatic warning which turns yellow at 0 V. Our battery, uniquely combined with these multiple smart features, represents solid progress in smart flexible electronics.

Ultracapacitors: Why, How, and Where is the Technology

Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Wearable biosensors for healthcare monitoring.

Abstract: Wearable biosensors are garnering substantial interest due to their potential to provide continuous, real-time physiological information via dynamic, noninvasive measurements of biochemical markers in biofluids, such as sweat, tears, saliva and interstitial fluid. Recent developments have focused on electrochemical and optical biosensors, together with advances in the noninvasive monitoring of biomarkers including metabolites, bacteria and hormones. A combination of multiplexed biosensing, microfluidic sampling and transport systems have been integrated, miniaturized and combined with flexible materials for improved wearability and ease of operation. Although wearable biosensors hold promise, a better understanding of the correlations between analyte concentrations in the blood and noninvasive biofluids is needed to improve reliability. An expanded set of on-body bioaffinity assays and more sensing strategies are needed to make more biomarkers accessible to monitoring. Large-cohort validation studies of wearable biosensor performance will be needed to underpin clinical acceptance. Accurate and reliable real-time sensing of physiological information using wearable biosensor technologies would have a broad impact on our daily lives.

Issues and opportunities facing aqueous zinc-ion batteries

Abstract: Zinc-ion batteries built on water-based electrolytes featuring compelling price-points, competitive performance, and enhanced safety represent advanced energy storage chemistry as a promising alternative to current lithium-ion battery systems. Attempts to develop rechargeable aqueous zinc-ion batteries (ZIBs) can be traced to as early as the 1980s; however, since 2015, the research activity in this field has surged throughout the world. Despite the achievements made in exploring electrode materials so far, significant challenges remain at the material level and even on the whole aqueous ZIBs system, leading to the failure of ZIBs to meet commercial requirements. This review aims to discuss how to pave the way for developing aqueous ZIBs. The current research efforts related to aqueous ZIBs electrode materials and electrolytes are summarized, including an analysis of the problems encountered in both cathode/anode materials and electrolyte optimization. Some concerns and feasible solutions for achieving practical aqueous ZIBs are discussed in detail. We would like to point out that merely improving the electrode materials is not enough; synergistic optimization strategies toward the whole battery system are also deeply needed. Finally, some perspectives are provided on the subsequent optimization design for further research efforts in the aqueous ZIB field.

Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry

Abstract: Aqueous zinc ion batteries (ZIBs) are truly promising contenders for the future large-scale electrical energy storage applications due to their cost-effectiveness, environmental friendliness, intri...