Breakthroughs in Solid-State Battery Technology Could Enable Electric Vehicles to Exceed 1000 km Range

Recent advancements by Chinese scientists have successfully addressed the critical issues surrounding all-solid-state lithium metal batteries, leading to a significant upgrade in battery performance. Previously, a 100-kilogram battery could only support a range of up to 500 kilometers; however, this breakthrough could potentially increase that range to over 1000 kilometers.

To understand this progress, it is essential to grasp the challenges that have prevented solid-state batteries from becoming mainstream. The operation of these batteries relies on lithium ions traveling between the anode and cathode. Essentially, lithium ions act like delivery personnel, transferring electrons from the positive to the negative electrode, with the solid electrolyte serving as their “highway.” Commonly used sulfide solid electrolytes are hard and brittle, while lithium metal electrodes are soft and malleable. When these two materials are combined, they create a poorly fitting interface, hindering the battery’s charging and discharging efficiency.

Fortunately, several research teams in China have made three significant technological breakthroughs that can enhance the compatibility between the solid electrolyte and lithium electrode, potentially resolving the interfacial contact issue and overcoming the range limitations of solid-state batteries.

The first breakthrough comes from a research team at the Chinese Academy of Sciences, which developed a “special adhesive”—iodine ions. During battery operation, iodine ions act like traffic police, moving toward the interface between the electrode and electrolyte under the influence of an electric field. They attract passing lithium ions, effectively filling any small gaps and ensuring a tight bond between the electrode and electrolyte. This innovation addresses the biggest bottleneck in making solid-state batteries practical.

The second breakthrough, termed “flexible transformation,” was achieved by scientists at the Chinese Academy of Sciences’ Institute of Metal Research. They created a framework for the electrolyte using polymer materials, enhancing the battery’s resistance to stretching and pulling, akin to an upgraded cling film. This structure can endure 20,000 bends and twisting without damage, making it resilient to everyday deformation. Additionally, by incorporating “chemical components” into the flexible framework, some components allow lithium ions to move faster while others increase lithium ion retention, resulting in an 86% boost in energy storage capacity.

The third breakthrough is known as “fluorine reinforcement,” developed by a research team from Tsinghua University. They modified the electrolyte with fluorinated polyether materials, which offer excellent high-voltage resistance. The fluorinated protective layer on the electrode’s surface prevents high voltage from “breaking down” the electrolyte. This technology has been tested under extreme conditions, including puncture tests and high-temperature scenarios, without causing explosions, ensuring both safety and range.

With these advancements, solid-state batteries are on the verge of turning the dream of electric vehicles with extended ranges into reality. Professor Huang Xuejie from the Chinese Academy of Sciences has highlighted that the recent research effectively tackles the challenge of achieving a tight interface between the solid electrolyte and lithium electrode in all-solid-state lithium batteries, allowing for normal operation without external pressure. Under standard testing conditions, these batteries have shown consistent performance even after hundreds of charge-discharge cycles, surpassing that of similar existing solid-state batteries.

The improvements in all-solid-state battery technology could revolutionize the electric vehicle sector. Professor Huang noted that eliminating the need for external pressure systems significantly increases the volume of active materials within the battery pack. By utilizing lithium metal anodes, the energy density of single batteries can exceed 500 Wh/kg, combined with the simplification of the solid-state battery system, which could lead to substantial increases in overall vehicle range.

Currently, mainstream lithium iron phosphate batteries have an energy density of approximately 200 Wh/kg, while ternary lithium batteries can reach up to 300 Wh/kg. Achieving an energy density of 500 Wh/kg would mean that batteries of the same weight could double the range of electric vehicles. Huang emphasized that this new technology not only simplifies manufacturing and reduces material costs but also enhances battery durability and safety.

Furthermore, this technology presents new pathways for reducing costs and improving efficiency within the electric vehicle supply chain. Presently, liquid lithium-ion batteries heavily rely on scarce metals like cobalt and nickel, which are limited in supply, subject to significant price fluctuations, and pose risks due to high import dependence. Huang stressed that this advancement paves the way for the use of abundant and cost-effective positive electrode materials such as sulfur, sulfides, and chlorides, reducing reliance on scarce metals and aligning with the sustainable development of battery materials.

In a global context, the research and development of all-solid-state batteries are still in a competitive phase, with Chinese scientists making significant contributions. Huang noted that this technological breakthrough marks a critical step in demonstrating the feasibility of using lithium metal or lithium alloys as the anode for inorganic solid-state batteries. This development signifies that China has transitioned from being a significant follower to becoming a partial leader in the next generation of battery technology, contributing to the global evolution of energy storage solutions.