Breakthrough coating promises longer-lasting, high-capacity lithium batteries

Researchers in China have developed a dual-shell coating that could make high-capacity lithium-ion batteries more durable, addressing long-standing problems with lithium-rich cathodes.

LiF@spinel design by a team of researchers from Hebei University and Longyan University unites two protective layers to prevent surface damage and improve cycling performance, offering a practical route to stable, high-energy batteries.

Lithium-ion batteries power most of today’s electric vehicles, smartphones, and renewable energy storage systems. They are lightweight, rechargeable, and pack a high energy density, making them vital for clean power transitions. Yet the technology faces hurdles.

Cathode instability, electrolyte breakdown, and gradual capacity fade shorten lifespan. Safety risks, such as overheating and fire hazards, also remain a concern. In addition, reliance on scarce metals like cobalt and nickel raises cost and supply chain issues.

These limitations drive research into safer, higher-capacity designs that can deliver longer life cycles and improved performance.

Shielding lithium-rich cathodesLithium-rich layered oxides (LRMO) have drawn attention for their high capacity and cost advantages. But oxygen release at high voltages, structural collapse, and corrosion from electrolyte breakdown limit their use. These issues trigger voltage decay and metal loss, slashing battery lifespan.

Coating strategies have been tested, but many block ion transport or peel off after repeated use. The LiF@spinel approach combines a spinel buffer for rapid ion movement with a LiF outer layer that blocks corrosive attack, the researchers said.

The coating was built using in situ reconstruction. A spinel layer formed directly on the cathode surface, creating a 3D network for lithium-ion transport. On top, a LiF shield chemically bonded with Ni–F anchors sealed the electrode against electrolyte attack.

Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the seamless integration of the two layers.

Tests showed strong results. At 2 C, the coated cathode retained 81.5% of its capacity after 150 cycles, compared with 63.2% for an uncoated sample. Even under ultrafast cycling at 5 C, the dual-shell design held more than 80% of its capacity. Electrochemical impedance results showed lower resistance, faster ion flow, and fewer corrosive by-products.