Materials for Energy Designing Optimized Materials for Emerging Energy Security Needs


Designing Optimized Materials for Emerging Energy Security Needs

Using advanced manufacturing and high-performance computing, Lawrence Livermore researchers are developing new materials for energy applications.

Amplifying U.S. Energy Supply to Increase Security

Achieving energy security requires both a robust domestic energy reserve and the capability for energy independence. Although the ability to harness energy from renewable sources has significantly improved, these developments introduce new challenges to the reliability of our nation's grid and transportation systems. From developing new storage materials to advancing infrastructure and technology for an emerging source such as hydrogen, the Laboratory's efforts are aimed at achieving a more secure, efficient, and sustainable national energy infrastructure.

Rendering shows hydrogen gas molecules.
This rendering shows how hydrogen gas molecules (gray spheres) can be stored inside solid lithium nitride confined within a carbon shell. (Rendering by Alexander Tokarev.)

Customizing Macrostructures for Distinct Applications

Topological optimization, which enables scientists to tailor the physical layout and properties of a material, is a key method used by Livermore researchers when developing new or improved storage materials. Using the Laboratory's state-ofthe- art additive manufacturing facilities, modeled macrostructure materials can be rapidly prototyped and tested for performance.

Applications for storage materials include battery electrodes with increased energy density and flow, fuel cells for hydrogenpowered energy, or laser targets for producing energy through nuclear fusion. One type of storage medium pioneered by the Laboratory is graphene aerogels, porous and high-surface-area conductive materials with hierarchical architectures that can be controlled at multiple scales. Using high-performance computing (HPC), Livermore researchers are designing custom graphene aerogels to increase energy storage capacity of batteries and supercapacitors. Aerogels can also be used to desalinate water—and potentially reduce the high amount of energy required to operate desalination plants—by flowing water through the aerogel electrodes while electrically charging and discharging them. In the process, charged sodium and chloride ions are captured on the electrode surface resulting in a desalinated water stream.

Advancing Solid-State Batteries for Improved Storage, Power, and Safety

Solid-state batteries (SSBs) are made with solid components instead of liquid electrolytes. This change has allowed them to outperform their counterparts in safety, stability, capacity, and power. However, manufacturing solid-state batteries that maintain mechanical integrity and performance is challenging, in part because of the brittle nature of many candidate materials. To overcome this limitation, Livermore researchers are working on a reliable three-dimensional (3D) printing method for producing a robust solid electrolyte using custom feedstocks. By properly tuning the feedstock and processing conditions, the material can be engineered to retain performance and integrity. Additive manufacturing can also be used to create complex shapes for optimizing power density in SSBs.

3d-printed supercapacitor electrode, made from a graphene aerogel.
Shown here is a 3D-printed supercapacitor electrode (made from a graphene aerogel) produced at Livermore.

Using HPC to Enable New Materials Discovery

Livermore's powerful HPC infrastructure provides a foundation to develop new types of energy materials. Using multiphysics science and engineering simulations spanning from the quantum to continuum scales, researchers can predict the composition and structure of a material designed to meet custom applications. Laboratory scientists can then additively manufacture prototypes and iterate with computational scientists to validate and improve the design.

For example, Livermore is using HPC to model interfaces between components within a solid-state lithium battery to understand the chemical reactions that limit cyclability and performance. By modeling the interface across a range of time and length scales (from the atomic to the device level), researchers can see how atoms and molecules redistribute, causing the battery to swell and fail over time. With this understanding, Laboratory scientists are investigating better ways to process battery interfaces to optimize performance and durability.

Shepherding Hydrogen into the Mainstream

Hydrogen—which can be made renewably by cleaving water molecules—has long been recognized as a clean energy source. In addition to supplying fuel cells for vehicle transport, it has the potential to provide reliable, long-term standby power for the electric grid. Yet, resulting from a lack of infrastructure for production and storage, hydrogen's promise has not been fulfilled. As part of the Department of Energy–funded Energy Materials Network (EMN), Livermore is focused on understanding the underlying technology limitations inhibiting widespread deployment of hydrogen. Laboratory researchers are leading EMN's multiscale modeling and simulation work for storage (HyMARC) and production (HydroGEN) programs. Livermore researchers are investigating a variety of materials for storing hydrogen in both atomic and molecular forms, including metal hydrides and graphene aerogels.

Looking Ahead

Future activities could include: (1) applying energy storage technology to new applications, including fast charge, pulsed power, directed energy, and long shelf life batteries; (2) optimizing interface composition and morphology for 3D-printed batteries; (3) engineering catalytic materials for low-temperature and high-temperature production of hydrogen and related energy carriers; and (4) understanding and mitigating materials degradation for a resilient and robust energy delivery infrastructure.