Research Interests

Advanced materials for nuclear energy applications

The extreme condition of advanced nuclear energy system requires revolutionary synthesis approaches to design and fabricate advanced materials for nuclear fuel, structural materials and waste form applications. Lian’s interests on Nuclear Materials are mainly focused on three key thrust areas: (1) development of advanced waste forms for specific waste stream (including actinides and fission products) associated with advanced fuel cycle processes; (2) design and characterization of advanced fuel materials with enhanced thermo-mechanical and accident tolerance for current LWR and advanced nuclear energy systems; (3) the development of advanced structural materials (such as oxide dispersion-strengthened alloys) and fundamental understanding of their performance under relevant nuclear application conditions. He is applying materials design strategies, specifically nano-scale manipulation and design based on recent advancements in fabricating nano-composites in materials communities, to develop advanced materials utilized as nuclear fuels, structural materials and waste form materials. Lian’s efforts under his NSF early Career award titled “Radiation Interaction with Nanostructured Ceramics” are focused on the development of advanced materials for better control of radiation through the nano-scale materials design concept.

Nuclear Engineering Advanced Modeling Simulations (NEAMS) and validation

The US Nuclear Energy Advanced Modeling and Simulation (NEAMS) program is developing science-based next generation fuel performance tools as part of its Fuels Product Line in order to create a predictive modeling capability for nuclear fuel performance and to assist the design and analysis of reactor systems. Multi-scale and Multiphysics fuel performance models (MARMOT models) on the key fuel properties have been developed, but not validated, and critical experimental data are needed to validate the developed MARMOT models. Grand scientific challenges exist in understanding the impact of microstructure on fuel properties without coupled complexity from irradiated fuels. Lian is performing state-of-the-art experimental work to obtain critical experiment data that can be coupled with NEAMS program for the development of high fidelity NEAMS fuel performance codes.

Materials behavior under extreme conditions

The materials behavior under extreme conditions will be central to every energy technology, and the extreme conditions also offer the possibility and flexibility to design materials by non-equilibrium approaches. It is critically important for developing advanced materials for harsh conditions often encountered in energy application environments including nuclear energy. Lian is particularly interested in promoting the fundamental understanding of materials under extreme conditions consisted of high temperature and intense radiation field and realizing the potential of materials design by extreme conditions. The fundamental understanding of materials behavior under extreme conditions will also have significant impacts on interdisciplinary fields of materials science, nuclear engineering, condensed matter physics and geological sciences. Lian is also working the science-based approaches for nano-scale materials design, assembly and manufacturing by extreme conditions with controllable characteristics of length scale, size and uniformity and exploring the potential applications.

Novel nanostructured materials for alternative energy applications

The development of alternative energy critically depends on the materials design and novel geometry with enhanced efficiencies for energy harvest, storage and utilization in which nanostructured materials play a key role. Lian is exploring scientific principles and new synthesis and assembly approaches that enable a science-based design of 3-dimensional geometry based on high energy density nanostructures to achieve transformational electrochemical performances. The 3-D nano-architecture with an open structure and high surface areas allow effective energy storage and efficient ionic and charge transport. He is working on the development of new materials or new strategies of designing and functionalizing high density electrodes to achieve exceptional rate performance, cyclic stability and excellent volumetric performance under a very high mass loading. Breakthroughs have been achieved in Lian’s groups for record-high cyclic stability and volumetric capacitance for both supercapacitors and LIBs.

Graphene and graphene-based nanocomposites

We has made important contribution to the development of large scale graphene on metallic substrates (Ni and Cu) by chemical vapor deposition, the milestone enabling next generation graphene-based electronics. The phenomenal works has led to the scientific breakthrough of fabricating high quality graphene on Cu foils. We are currently working on the graphene and graphene-based nanocomposites by synergizing high energy density nanostructured materials with highly conductive graphene network to achieve simultaneously high energy and power densities for both supercapacitor and battery applications. We are also actively working on the exploration of graphene and graphene-based nanocomposites for a wide range of technological applications including thermal energy storage, photocurrent detector, sensors/actuators, photocatalysts and thermal energy managements.

Scale-up manufacturing of macroscopic graphene

Graphene, a single layer of carbon atoms bonded in a hexagonal lattice, is simultaneously the thinnest, strongest and stiffest known material, as well as being an excellent conductor of both heat and electricity. The reassembly of individual 2D graphene nanosheets into 3D macroscopic structures such as films, papers or fibers offers immense potentials for many important applications such as structural composites, electrodes for batteries, super-capacitors and fuel cells, optically transparent films for solar cells, stretchable/foldable electronics, bio-chemical sensors, corrosion resistant coatings, dielectrics, photo-catalysts, and membranes for gas separator, next generation nano-filtration and desalination technologies. However, key challenges exist in the scalable and cost effective assembly of 2D graphene nanosheets into 3D macroscopic structures and to maintain exceptional properties. Breakthrough technologies have been developed in Lian’s lab for assembly of highly flexible and large area graphene paper, and highly thermal-conductive and mechanically strong graphene fibers that can unlocking the enormous potentials for graphene-based macroscopic structures.

Plasmonic nanostructures and new perovskite structures

The rapid development of nanoscale plasmonic structures and their hybrids with semiconducting supports represents an exhilarating and promising solution potentially improving light absorption and fast charge separation kinetics of semiconductors. The enhanced light absorption in visible light regime and fast charge separation are critical for many applications such as photo-catalysts in decomposing contaminants, water splitting, and photovoltaics. Lian is working actively on the plasmonic nanostructures to enhance light adsorption and photoluminescence for photocurrent detectors and sensors. On the other hand, organic halide perovskite is revolutionizing the photovoltaics by achieving a record-high solar-to-electrical conversion efficiency resulting from its exceptional light absorption, unprecedented charge carrier lifetime and charge separation efficiency, but the organic halide perovskite is limited by the high toxic of lead and phase instability. Lian is also exploring alternative inorganic lead-free perovskite to drastically improve the stability and thus functionalities of perovskite materials.