Lithium-ion batteries and accumulators are valued for their ability to store large amounts of energy in a small volume, making them the battery of choice for multiple applications ranging from electric vehicles to laptops and smartphones among many others.  

As demand for better-performing battery technology grows, safety remains a key factor to consider when developing new battery materials. Currently, commercial-grade lithium-ion batteries carry the risk of swelling and exploding when the battery is exposed to a rapid increase in temperature. This phenomenon, called thermal runaway, occurs when the battery’s electrolyte comes into contact with oxygen, which can be caused by damage to the battery cell, exposure to direct sunlight or manufacturing defects.  

The electrolyte is a component that plays a key role in battery function, enabling the transfer of ions between electrodes, which is essential for energy storage and release during charging and discharging. To ensure battery safety, it is imperative to prevent the electrolyte formulation from decomposing and aging, and to avoid contact with impurities, foreign particles, or oxygen.  

Measuring and controlling the density of the electrolyte is the primary method for assessing its composition. Since the electrolyte’s density should remain constant during charging and discharging, it is often used as a reliable quality control measure to ensure the composition meets all manufacturing requirements and addresses potential safety issues.  

Use case: Simulations of electrolyte density with QuantistryLab  

Simulations offer a time- and cost-effective alternative to experimental methods when it comes to calculating the density of an electrolyte formulation. Based on the principles of molecular dynamics, this approach can be seamlessly integrated into R&D workflows to accelerate the design and development of new electrolyte formulations with the desired specifications for any application of choice.  

With just a few clicks, QuantistryLab enables the user to run simulations of electrolyte formulations, modelling and predicting a variety of key properties, including density.  

To this end, molecular dynamics simulations can be employed to simulate the average density of a chemical system over time, under selected conditions of temperature and pressure. This process involves a preparatory stage where a series of simulations bring the system to thermal equilibrium, with the goal of enabling reliable predictions of its properties.

In QuantistryLab, this entire simulation workflow — from electrolyte formulation design to equilibration, production, and property estimation like density — is fully automated. Users simply select their system and run the density calculation with just a few clicks through a web browser. This streamlined approach was applied in this use case.

Besides the environmental conditions, the chemical composition of the electrolyte is the primary factor determining its density. The electrolyte formulations chosen for this use case are based on organic solvents commonly used in lithium-ion batteries. Modern batteries typically use mixtures of these carbonate solvents in combination with additives to optimize the electrolyte’s performance:  

• Ethylene carbonate (EC)  

• Dimethyl carbonate (DMC)  

• Diethyl carbonate (DEC)

• Ethyl methyl carbonate (EMC)

Density calculations were performed for each of the solvents at 100% purity, as well as for various combinations of the solvents at different weight ratios, with lithium hexafluorophosphate (LiPF6) added as the lithium salt. Models of all these chemical systems were prepared in QuantistryLab by simply selecting the desired components from the compound library and setting the intended ratio. All density calculations were performed at a temperature of 20 °C and pressure of 100 kPa.

The five chemical systems simulated were the following:

• System 1: 1M LiPF6 in EC:DMC (1:1 vol.%)

• System 2: 1M LiPF6 in EC:DEC (1:1 vol.%)

• System 3: 1M LiPF6 in EC:EMC (1:1 vol.%)

• System 4: 1M LiPF6 in EC:DEC:DMC (1:1:1 vol.%)

• System 5: 1M LiPF6 in EC:EMC:DMC (1:1:1 vol.%)

The results of the simulations show a strong agreement with experimental data reported for the density of the same solvents and electrolyte formulations. The collection of data demonstrates the predictive power of the QuantistryLab platform to determine the density, not only for pure materials but also for complex chemical systems composed of multiple compounds.  

In addition to the density feature, QuantistryLab offers a comprehensive range of simulation tools that provide accurate calculations of key properties of the electrolyte, such as viscosity, while also delivering quantitative insights into electrolyte decomposition and aging processes. Altogether, this toolbox is designed to be seamlessly implemented in battery R&D workflows, accelerating the development of new battery materials with enhanced performance and safety.

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