Battery Life can be Enhanced by up to 44% Thanks to the New Prelithiation Technique

Rice University researchers have identified a scalable method for extending the lifespan of lithium-ion batteries using prelithiation, a technique that covers silicon anodes with stable lithium metal particles, which can boost battery life by up to 44%.

The ability of silicon anode batteries to revolutionize energy storage technologies is critical in fulfilling climate objectives and realizing the full promise of electric cars.

Nonetheless, the ongoing depletion of lithium ions in silicon anodes poses a substantial barrier to the development of next-generation lithium-ion batteries.

Scientists at Rice University’s George R. Brown School of Engineering have discovered a method for enhancing prelithiation that involves coating silicon anodes with stabilized lithium metal particles (SLMPs) to limit lithium loss and boost battery life cycles.

Sibani Lisa Biswal, a chemical and biomolecular engineer at Rice University, revealed that spray-coating anodes with a mixture of the particles and a surfactant extends battery life by 22% to 44%. Initially, higher-coated battery cells offered greater stability and cycle life. The drawback was that when the battery was cycled at full capacity, a higher quantity of the particle coating generated more lithium trapping, leading the battery to fade faster in subsequent cycles.

The replacement of graphite for silicon in lithium-ion batteries would result in a large improvement in energy density, which would be better for weight and size. This is due to the fact that graphite, which is comprised of carbon, can hold fewer lithium ions than silicon, and it takes six carbon atoms to bind with a single lithium ion, whereas only one silicon atom can link with four lithium ions.

Biswal stated that silicon may improve the energy density of anodes in lithium-ion batteries, which is why there is a drive in battery research to replace graphite anodes with silicon anodes, but other features of silicon pose issues as well.

According to Biswal, the existence of a solid-electrolyte interphase (SEI) layer in silicon is a serious concern since it consumes lithium.

The electrolyte of a battery cell interacts with electrons and lithium ions to form a layer of salts on the anode. This layer protects the anode’s electrolyte and prevents additional reactions. However, the SEI can fail during further charge and discharge cycles, depleting the battery’s lithium reserve irreversibly.

According to Quan Nguyen, the study’s primary author and a doctorate student in chemical and biomolecular engineering, the volume of the silicon anode can change when the battery is cycled, causing instability or breaking the SEI.

Biswal and her colleagues created prelithiation, which enhances the stability of the SEI layer, resulting in a reduction in the amount of lithium ions lost during its development.

Biswal noted that prelithiation is a technique used to compensate for the lithium loss that happens with silicon. This is comparable to the priming procedure used for painting a surface, such as a wall, when an undercoat is required to ensure the paint adheres to the wall. Prelithiation allows the battery to “prime” its anodes, which results in a more stable and long-lasting battery.

Despite the fact that these particles and prelithiation are not novel, the Biswal lab was able to optimize the technique in a way that is now widely used in battery manufacture.

Quan devised a surfactant to disperse particles, which is a revolutionary approach that assures uniform dispersion rather than lumps or pockets within the battery, according to Biswal.

Nguyen pointed out that if the particles are combined with a solvent other than the surfactant, a homogenous coating cannot be formed. Furthermore, spray-coating outperformed alternative techniques of evenly distributing anodes. According to Nguyen, large-scale production is a viable alternative for the spray-coating approach.

Reference: “Prelithiation Effects in Enhancing Silicon-Based Anodes for Full-Cell Lithium-Ion Batteries Using Stabilized Lithium Metal Particles” by Quan Anh Nguyen, Anulekha K. Haridas, Tanguy Terlier and Sibani Lisa Biswal, 1 May 2023, ACS Applied Energy Materials.