INTERVIEW | Dr. Billy Wu: LFP has emerged in the last few years as a key technology for EVs.

Dr. Billy Wu is an Associate Professor at Imperial College London, where he is the Director of Research in the Dyson School of Design Engineering. He leads a research group which works at the interface between fundamental science and engineering application of electrochemical energy storage and conversion technologies. Cross cutting activities include: energy materials, modelling, characterisation, control, system design and techno-economics.

Notable battery activities include work on multi-scale modelling with the Faraday Institution, where he also chairs their Training and Diversity panel. So, we discussed with Dr. Wu regarding latest LFP batteries trends and situation in our industry.

How do you assess the role of LFP (lithium-iron-phosphate) chemistry in scaling cost-effective EV adoption globally, especially considering current research on battery degradation and thermal resilience?

LFP has emerged in the last few years as a key technology for EVs. Despite having a lower cell level energy density compared to high-nickel chemistries, the lower cost cathode materials alongside robust safety characteristics, have demonstrated that system level performance gains can be made, towards enabling scalable LFP systems for automotive. Furthermore, the robust crystal structure of LFP enables excellent cyclability, towards long lifetime systems.

With LFP’s absence of cobalt and nickel, to what extent can it mitigate ethical and geopolitical supply risks, while still addressing energy density and range concerns?

Firstly, with the continued electrification of many applications, we are likely to need a diversity of different battery chemistries, so nickel containing cathodes are likely to continue to be important. However, LFP of course has advantages in terms of reducing the need for nickel which has been forecasted to be a potential bottleneck in scaling depending on demand.

Photo: Bloomberg

Given LFP’s growing dominance in grid-scale energy storage, what are the key advantages and limitations when designing BESS based on this chemistry?

The low cost and generally good safety characteristics of LFP have seen the chemistry take a leading position in BESS, however there are still some challenges. One of these includes LFPs flat voltage curve which makes accurate estimation of state-of-charge in real-world conditions challenging. Overtime and in certain operating conditions, these errors in state-of-charge estimation can accumulate, affecting the ability of the BESS system to effectively perform energy services such as arbitrage.

From your research into degradation and thermal gradients, what strategies can optimize the lifetime and safety of LFP-based BESS, especially in extreme climates?

Batteries are extremely temperature sensitive. Too cold and this can result in an effect called lithium plating, too hot and this can accelerate side reactions; both of which can accelerate degradation. In extreme environments, the thermal management system of a BESS is therefore critical to ensure long lifetime performance, with temperatures ~25°C often ideal. Here, managing the state-of-charge which the system sits at most of the time can also have a key influence, with high state-of-charge generally accelerating degradation.

Your work integrates multi-scale battery modelling and hybrid digital twins. How can these tools support design optimization for LFP modules used in both EV and stationary storage applications?

Batteries, especially for BESS, are getting larger towards enabling lower cost ($/kWh). This increasing scale whilst lowering cost can result in effects such as thermal gradients and internal stresses manifesting in the cell, causing localised degradation in the cell which can then spread to the rest of the system. Thus, larger cells generally are less homogeneous in performance than smaller cells. Having models which can capture local electrochemical performance and translate this to a system is therefore essential for forecasting and prolonging lifetime. Battery digital twins fuse real-time sensor data with models, providing an up-to-date digital representation of a physical system and subsequent asset-specific optimal decisions, allowing us to apply customised operating conditions to cells as they age.

What are the main electro-chemo-thermal-mechanical challenges you’ve seen in LFP cells, and how do they inform new approaches in cell architecture and thermal management designs?

Whilst the LFP electrode is quite stable, the anode still poses various challenges. Generally this is graphite in a LFP cell, and at high rates of operation and low temperatures, lithium-plating can occur on the anode. This plated lithium can in turn react with the electrolyte. The graphite can also expand and contract. Overtime, degradation effects can cause the cell the physically expand causing issues to mechanical stability at the cell and system level.

You explore emerging electrode materials like silicon–graphite blends and metal‑air systems, how do these innovations compare to LFP in terms of cost, complexity, and readiness?

Silicon-graphite and metal-based electrodes are generally applied to the anode. They can also be applied to LFP, however there are still challenges to be overcome in terms of the first cycle columbic efficiency (i.e. how reversible the reaction is). Generally, the use of these materials beyond graphite offer increased energy densities but at the trade-off of cost. As such, there are more limited examples of systems like LFP-Graphite/Silicon and LFP-Lithium metal, though it can be done.

Your portfolio spans supercapacitors, fuel cells, and flow batteries. Where do you see potential synergies between LFP-based systems and these alternative energy storage technologies?

Each general electrochemical technology and the subset of each, has pros and cons, and will likely play a round in our future energy system. For technologies such as fuel cells, these generally have high theoretical energy densities, but have more limited power density. Similarly, flow batteries can be scaled to store significant amounts of energy, however in both cases, the power densities of these systems are more limited, opening the possibility of hybrid systems which combine energy-focused and power-focused systems.

Considering Europe’s push to reduce reliance on Chinese batteries, what role could advanced LFP cell manufacturing, with insights from your modelling and design work, play in European energy security and innovation?

The majority of cells are manufactured currently in China. From an energy security and general energy resilience perspective, a diverse supply chain of battery technologies no doubt will be advantageous. The battery market is however highly competitive and China has manufacturing excellence in this area alongside a mature manufacturing industry. Innovations in this area are still possible, however we have to approach this with an intelligent approach. Models can play a key role in this; enabling the digital design of new cell formats and electrode designs in-silico, lowering cost and accelerating development. Running advanced models in parallel with this will also enable system operators to get the most out of the system.

What policy or industry-level measures (e.g. subsidies, regulatory mandates) do you believe are most critical to enable adoption of LFP in both EV and grid storage markets, based on techno‑economic modelling experience?

Subsidies are of course welcome when deploying promising early stage technologies, however in the long term should ideally not remain in place forever. Batteries have come down significantly in price and cost parity is being reached with other technologies, however there are now different challenges. With BESS specifically, current system deployments are significant in size, meaning that total system costs are in the many millions. This naturally raises challenges around financing, insurance and other practical elements of implementation. Furthermore, de-bottlenecking the process of connecting large scale BESSs to the grid also needs consideration.

Read previous interview here.