Do you want to contribute to a more sustainable world? Are you excited to deploy computational chemistry and materials science to help shape the future of battery technology and consequently the future of consumer electronics and mobility?

About LeydenJar
LeydenJar aims to become the world’s innovation leader in advanced battery anodes to energize batteries for human progress. High energy density of battery cells is an urgent and unmet need for a wide range of industries from consumer electronics to electric vehicles. By addressing the bottleneck of the battery anode, LeydenJar can improve this by 50-70% in an industry that can only improve 3% per year. Our pure silicon anode is regarded as the holy grail to achieve this in the battery industry. Progress is not only about enabling new products, it also means a more sustainable supply chain, resilience and access to battery technology in geopolitical context and enabling electrification.

Further advancement of durable performance under a wide range of conditions (high voltage, high/low temperatures, fast charging) requires a fundamentally deeper understanding of electrolyte behavior and interfacial chemistry. We are building internal computational capability to accelerate electrolyte development and reduce experimental iteration cycles. This role of Computational Chemist is central to that effort.

Your mission
As a Computational Chemist at LeydenJar, your mission is to generate mechanistic insight into liquid lithium-ion electrolytes and their interactions with 100% silicon anodes. You will develop and deploy atomistic simulation frameworks that convert complex molecular behavior into physically interpretable descriptors and predictive insights.

Your work will directly accelerate electrolyte development, reduce experimental iteration cycles, and improve high-temperature and high-SOC performance of our next-generation battery technology.

Your primary location will be Leiden. You may occasionally be required to work at our Eindhoven site.

You will join the Battery R&D team under the CTO line and work closely with Battery R&D, Product Development, and Machine Learning/Data Engineering colleagues. Together, you will translate atomistic simulations into structured datasets, predictive features, and actionable guidance for experimental programs.

You will help build LeydenJar’s internal computational capability from the ground up, operating at the intersection of electrochemistry, materials science, and data science. You are expected to deliver rigorous science with startup-level speed and pragmatism.

Your responsibilities:

• Design, build, and validate atomistic simulation frameworks (density functional theory DFT, molecular dynamics MD, and related methods) for liquid electrolytes and their interfaces with silicon anodes and lithium-ion cathodes.

• Quantify bulk electrolyte properties such as solvation structure, ion pairing, transport behavior, and thermodynamic stability under relevant operating conditions.

• Investigate interfacial reactions and decomposition pathways related to SEI formation, oxidative stability, and high-temperature degradation.

• Derive physically interpretable descriptors from simulation outputs and structure them for integration into internal machine learning pipelines.

• Collaborate closely with machine learning scientists, battery scientists and data team to translate battery performance questions into focused computational studies.

• Develop clean, reproducible Python code for simulation analysis, data processing, and workflow automation.

• Build and maintain scalable, automated simulation workflows to enable efficient and reproducible studies.

• Support force field parameterization, validation, and benchmarking where required.

• Operate effectively with complex, evolving, and sometimes incomplete experimental data.

• Use version control (e.g., Git) for collaborative development of scripts, analysis tools, and workflows.

• Clearly communicate modeling assumptions, limitations, uncertainty, and conclusions to multidisciplinary stakeholders.

About you:

• PhD (preferred) or Master’s degree in Computational Chemistry, Computational Materials Science, Physics, Chemical Engineering, or a related field.

• Strong hands-on experience with atomistic simulation methods (DFT and molecular dynamics). Experience modeling liquid systems and electrolyte chemistry is strongly preferred.

• At least 2 years of industry experience applying computational methods to practical materials or chemical problems.

• Strong Python programming skills, including scripting, data analysis, and workflow automation.

• Demonstrated ability to extract physically meaningful descriptors from simulation data and link them to experimental behavior.

• Experience with reproducible workflows and version control systems (e.g., Git).

• Comfortable working independently in a fast-paced and agile startup environment.

• Clear communicator who can explain modeling choices, assumptions, and uncertainty to experimental and leadership audiences.

• Strong ownership mindset and pragmatic problem-solving approach.

• Fluent in English.

Additional desirable experience:

• Experience modeling complex systems with limited or noisy experimental validation data.

• Exposure to setting up high-throughput or automated simulation workflows.

• Experience generating datasets for machine learning applications, including descriptor engineering or active learning approaches.

• Experience contributing to HPC or cloud-based computational infrastructure setup.

• Experience working with cloud platforms for large-scale simulation or data storage.

Why LeydenJar?

• Unleash Your Potential: Step into a workplace where growth and ownership go hand in hand. We empower every individual regardless of background, gender, or identity to thrive and achieve their career aspirations.

• Pension & Insurance Security: We care about your future. LeydenJar contributes 10% on top of your monthly gross salary toward your pension and life insurance, ensuring long-term security for you and your loved ones.

• Recharge & Refresh: Enjoy 25 vacation days per year (based on full-time hours) because work-life balance is essential for everyone.

• Travel Made Easy: We cover your home-to-work travel costs with €0.23 per kilometer or provide an NS Business Card for hassle-free public transportation.

• Continuous Learning: Access our online learning platform (Udemy) to develop your skills and unlock new opportunities for personal and professional growth.

• Diverse, Inclusive & Equal: Be part of an international team of 20+ nationalities, where everyone’s voice matters, and where diversity, equity, and inclusion are more than values they’re actions.

• Community & Connection: From team-building events and monthly lunches to year-end celebrations and inclusive gatherings, we create spaces where everyone feels welcome and engaged.

Do you want to take on the challenge as Computational Chemist?

We are looking forward to your application!

If you'd like to learn more about LeydenJar amazing team, see below:

At LeydenJar we value diversity, and we provide equal opportunities to all applicants without regard to race, color, ethnicity, religion, gender, pregnancy/childbirth, age, national origin, sexual orientation, disability, etc. If there are two or more applicants of equal suitability for a certain position, LeydenJar can under circumstances decide to select applicants based on positive discrimination in full compliance with all relevant and applicable law.