Can Solid-State Batteries Recharge the Future of Electric Cars?

Technical Input By

Written by Erica Eggleton, PhD

October 28, 2022

Solid-state batteries are appearing more frequently in conversations surrounding the future of electric vehicles (EVs). These batteries promise faster charging rates, improved vehicle range, and enhanced longevity, as researchers and start-ups strive to bring this “holy grail” technology to market.

The opposite of solid is…liquid?

Typically, electric vehicles utilize Lithium-ion (Li-ion) batteries. Each Li-ion battery consists of two electrodes separated by an electrolyte that enables lithium ions to travel between them.

The anode is typically made of graphite, while the cathode often comprises metallic lithium or a lithiated metal oxide. Most lithium-ion batteries contain a liquid electrolyte. In contrast, solid-state batteries utilize a solid electrolyte.

How is solid-state better?

Solid-state batteries aim to alleviate three key concerns for EV consumers: range, charging time, and safety.

Better Range with Solid State

An EV must have a means to store more energy to enhance its range. While increasing battery size can yield some benefits, it can also add significant weight. Instead, solid-state batteries offer a way to increase energy density—measured in kilowatt-hours (kWh) or watt-hours (Wh) per pound or kilogram. Solid-state batteries are projected to possess about double the energy density of standard Li-ion batteries.

Battery Type and Typical Energy Density Range (Wh/kg):

• Lead acid: 30-50
• Nickel-Metal Hydride (NiMH): 60-120
• Lithium Iron Phosphate (LFP): 90-120
• Lithium Manganese Oxide (LMO): 100-150
• Nickel Manganese Cobalt (NMC): 150-220
• Nickel Cobalt Aluminum Oxide (NCA): 200-260
• Solid state: 300-400+

Other alternatives such as lithium-metal batteries, using solid lithium as the anode, can store more energy but come with safety concerns — especially when used in liquid-electrolyte batteries where dendrites can cause short-circuits.

Solid electrolytes present a solution to these safety issues by acting as a barrier between electrodes, reducing concerns when battery damage occurs.

Safer Rides with Solid State

The heat-resistance and material stability of solid-state batteries make them safer during collisions, mitigating risks of fire or leakage.

Limitations to Adoption

Despite their benefits, the technology faces hurdles, primarily due to higher production costs and limited data from current small-scale manufacturing.

Current Developers

Notable businesses in this space include QuantumScape, which is backed by Volkswagen Group, and Toyota, with plans for a hybrid solid-state battery vehicle by 2025. Other candidates are Solid Power, expecting commercial cells by 2027.

Other Uses for Solid State Batteries

Solid-state batteries have further applications in electric aviation, where reducing weight is pivotal. NASA’s SABERS program reports a 30-40% reduction in battery weight using solid-state technologies.