Lithium-ion technology looks set to remain a fixture in electric vehicles for the foreseeable future. Their position at the top of the sector reflects years of technological refinement, reduced production expenses, and a well-established supply chain network.

Scientists and battery manufacturers are exploring alternative chemistries that aim to lessen reliance on lithium and other raw materials, enhance safety, or achieve substantially greater energy storage capacity. Some technologies have already entered production, while others are still at the experimental stage; among them, sodium-ion batteries stand out as the leading contender to lithium-ion in terms of readiness for broader commercial deployment.

Operating on comparable technology, sodium-ion batteries swap out lithium for sodium, a naturally plentiful and readily accessible element. Sodium-ion vehicles have begun appearing on Chinese roads, with leading battery producers CATL and BYD among those expanding production of the technology.

Energy density remains the key constraint. Current sodium-ion cells achieve energy densities of approximately 175 Wh/kg, while LFP technology tops out near 205 Wh/kg and certain NMC chemistries deliver around 265 Wh/kg. This characteristic positions them as a practical choice, at present, for compact electric vehicles, city transport, and commercial uses where extended driving range is not a primary requirement.

Solid-state batteries, which swap out the flammable liquid electrolyte used in standard lithium-ion cells for a solid alternative, represent a different technological approach. The approach holds out the prospect of enhanced safety and a potentially far greater energy density, especially when combined with lithium-metal anodes. The advance in technology has the potential to extend vehicle range without a proportional increase in battery dimensions or mass.

Production remains the primary obstacle. Solid-state technology continues to face high manufacturing costs and scalability challenges, while its performance benefits over conventional batteries have yet to be proven in mass-market vehicles.

Lithium-sulfur chemistry, by contrast, holds the potential for substantially greater energy storage capacity, a property that positions it as a promising option for extended-range and heavier electric transport applications. Sulphur is both plentiful and low-cost, and the chemistry behind it offers the capacity to hold far greater energy per unit of weight than standard lithium-ion cells. Lithium-sulfur technology has been flagged by the IEA as a promising advancement for vehicles and vessels with high power demands, such as electric trucks, boats, and aircraft.

Longevity, however, continues to present a challenge. Existing versions face constraints such as restricted battery longevity and various engineering hurdles that have slowed broader adoption in the marketplace. A new comparative study identified cost and environmental drawbacks in current lithium-sulfur battery configurations.

Magnesium-ion designs offer an alternative by substituting magnesium — a widely available element capable of transferring two electrons per ion — for lithium. This property may enable magnesium-based batteries to hold considerably larger quantities of stored energy. Magnesium's broader accessibility also positions it as a viable alternative that could ease strain on lithium supply networks.

Magnesium ions bind tightly to electrode and electrolyte materials, a property that researchers have found poses obstacles to building batteries capable of sustaining reliable charge and discharge performance across multiple cycles. At present, magnesium-ion technology sits largely within laboratory and development environments, with commercial deployment in electric vehicles still some way off.

Zinc-based batteries are drawing growing interest from researchers owing to zinc's wide availability, low cost, and its compatibility with water-based electrolyte systems that lend themselves to safer battery architectures. Zinc-ion and zinc-air battery technologies are among those under active development for power storage and a range of other uses. Among the noted benefits are cheaper raw materials and a lower likelihood of fire.

Two limitations they face are storage capacity and the ability to recharge. Zinc-based battery technology requires further development to match the energy density and compact form demanded by passenger electric vehicles. Certain newer research points to encouraging results in cycle durability, though much of this technology remains more applicable to fixed energy storage systems than to automotive use at present.

The road ahead is unlikely to see any single alternative displace lithium-ion across all vehicle categories. Sodium-ion technology may suit lower-cost urban vehicles, solid-state designs appear better matched to high-end long-range electric cars, and lithium-sulfur variants are being explored for heavier electric transport applications. Alternative battery technologies are likely to find roles in niche or specialised uses.

Lithium-ion battery technology continues to hold a leading position among competing energy storage options. Development of a replacement system, or multiple systems, is already in progress.