## 1 Introduction  
One of the biggest challenges facing modern society is the transition to a sustainable model based on renewable resources, which requires solving our heavy reliance on fossil fuels. This transition is essential to mitigate climate change, reduce carbon emissions, and ensure long-term energy security. However, achieving this shift is not straightforward and involves overcoming significant obstacles, such as the intermittency of renewable energy sources like solar and wind, whose production is variable, dependent on weather conditions and time of day. To address this challenge, it is crucial to improve the performance of existing energy storage technologies, which play a key role in stabilising the grid, allowing for excess energy generated during periods of high production to be stored and then released during periods of low production. The current scenario of the battery market is dominated by lithium-ion batteries (LIBs), which have become the preferred choice due to their numerous advantages over other battery systems, such as high specific capacity and voltage, absence of memory effect, excellent cycling performance, low self-discharge, and wide temperature range of operation [1; 2]. Nevertheless, many of the currently available energy storage devices, like LIBs, face limitations in terms of energy capacity, charging times, lifespan, and cost. Enhancing these devices to store larger quantities of energy, charge more efficiently, last longer, and remain cost-effective is critical for enabling the widespread adoption of renewable energy. Carbonates are essential components of both current lithium-ion batteries (LIBs) and the interesting alternative of lithium metal batteries (LMBs), which use more concentrated electrolytes to increase their performance [3] and in new configurations under study as, for example, high-entropy electrolytes [4]. Among the many carbonates available, ethylene carbonate (EC) stands out due to its high dielectric constant, a desirable characteristic for an electrolyte. However, EC has a relatively high melting point (36 \({}^{\circ}\)C), which limits its performance at lower temperatures [4; 5]. To address this issue, linear carbonates such as dimethyl carbonate (DMC) or diethyl carbonate (DEC), can also be added to the previous electrolyte mixture to improve their fluidity by reducing viscosity and lowering the melting temperature. Consequently, LiPF\({}_{6}\)/linear carbonate(s)/EC [6] has become one of the most widely used and popular electrolyte formulations in today's industry due to its balanced performance in terms of conductivity, thermal stability, and operational temperature range. Nevertheless, linear carbonates pose significant safety concerns due to their low flash point, which is near room temperature [7]. This makes them highly flammable under thermal, electrical, or mechanical stress, potentially leading to severe consequences such as fire and/or explosion [8], especially in battery packs composed of thousands of cells. The combination of ionic liquids (ILs) with cyclic carbonates has emerged as a promising electrolyte for various electrochemical applications, providing a safer and more reliable option compared to traditional linear carbonate-based electrolytes [8; 9]. Different carbonates and even water are also cosolvents of greatest interest as is widely pointed out in recent literature [10; 11; 12; 13; 14; 15; 16]. ILs are ionic compounds with a melting point below 100 \({}^{\circ}\)C, consisting of an organic cation and a weakly coordinated inorganic or organic anion. They are particularly attractive due to their non-flammability, negligible vapour pressure, good ionic conductivity, wide electrochemical window, and high chemical and thermal stability. These unique properties make ILs highly versatile for a broad range of applications, including their use as solvents, lubricants, and electrolytes [7].