Yuan Ji

Bio: Yuan Ji is an academic researcher from Nanjing Forestry University. The author has contributed to research in topics: Electromagnetic shielding & Virology. The author has an hindex of 1, co-authored 2 publications receiving 3 citations.

Flexible TaC/C electrospun non–woven fabrics with multiple spatial-scale conductive frameworks for efficient electromagnetic interference shielding

Abstract: Efficient, flexible, thin, and easy processing electromagnetic interference (EMI) performance materials attract attention to prevent increasingly electromagnetic pollution. Herein, we fabricated multiple spatial-scale conductive frameworks containing tantalum carbide (TaC) nanoparticles by electrospinning and high-temperature pyrolysis. The electrospun composite fabrics possess outstanding properties such as an excellent tensile strength of 9.5 MPa and excellent flexibility. Furthermore, the TaC nanoparticles with appropriate concentration can interconnect with each other endowing the composite fabrics with high electrical conductivity of 10.4 S cm−1. It also has great EMI SE of up to 37.7 dB in X band with only 0.2 mm thickness, and the SSE/t values of 4290.1 dB cm2 g−1. Owing to its pore structure, the shielding mechanism is mainly based on reflection and the finite element simulation further visually confirmed the excellent shielding capabilities. This novel electrospun composite fabrics have a great potential to be applied in fields of aerospace, and electronic devices.

High strength, flexible, and conductive graphene/polypropylene fiber paper fabricated via papermaking process

Abstract: Graphene paper with good mechanical strength, flexibility, and high conductivity is an emerging functional material for wide applications, but its feasible and scalable preparation remains a challenge. Herein, a high strength, flexible, and conductive graphene/polypropylene (PP) fiber paper was prepared by a traditional papermaking process. In the composite paper, graphene nanosheets were well stabilized on the PP fibers forming a stable three-dimensional conductive interleaved network. Chitosan was found able to build a polar active interface on PP fibers and graphene nanosheets, which can not only promote PP fiber dispersion in water yielding a uniform pulp, but also favor the retention of graphene in the composite paper. As a result, the composite paper presents high strength (15.32 MPa), good conductivity (11,995 S/m), shielding effectiveness (31.1 dB), water resistance, fungi-proof, and thermal conductivity (10.17 W m−1 k−1) properties. This work demonstrates the feasibility of large-scale preparation of graphene composite paper with commercial synthetic fibers through a traditional papermaking process, and expands the potential industrial application of graphene materials. Graphene/chitosan co-aggregates were absorbed on the surface of graphene/chitosan/PP fiber under the electrostatic interaction of CPAM to form graphene/PP fiber.

Laminated Structural Engineering Strategy toward Carbon Nanotube-Based Aerogel Films

Abstract: Aerogel films with a low density are ideal candidates to meet lightweight application and have already been used in a myriad of fields; however, their structural design for performance enhancement remains elusive. Herein, we put forward a laminated structural engineering strategy to prepare a free-standing carbon nanotube (CNT)-based aerogel film with a densified laminated porous structure. By directional densification and carbonization, the three-dimensional network of one-dimensional nanostructures in the aramid nanofiber/carbon nanotube (ANF/CNT) hybrid aerogel film can be reconstructed to a laminated porous structure with preferential orientation and consecutively conductive pathways, resulting in a large specific surface area (341.9 m2/g) and high electrical conductivity (8540 S/m). Benefiting from the laminated porous structure and high electrical conductivity, the absolute specific shielding effectiveness (SSE/t) of a CNT-based aerogel film can reach 200647.9 dB cm2/g, which shows the highest value among the reported aerogel-based materials. The laminated CNT-based aerogel films with an adjustable wetting property also exhibit exceptional Joule heating performance. This work provides a structural engineering strategy for aerogel films with enhanced electric conductivity for lightweight applications, such as EMI shielding and wearable heating.