Battery capacity decay reduced by almost 50% with cathode improvement

Researchers at Skoltech in Russia have developed an improved cathode material for lithium-ion batteries by doping it with a small amount (0.5 mole percent) of tantalum oxide (Ta₂O₅). This modification significantly reduces the rate of battery capacity decay per cycle by nearly 50%, thereby enhancing battery lifespan. The breakthrough addresses a key challenge in nickel-rich layered oxide cathodes, which store more energy but degrade faster due to crack formation during repeated charging and discharging. The team created a concentration gradient structure in the cathode particles, with nickel content highest at the center and increasing manganese and cobalt stabilizers toward the surface. They developed a mathematical model accounting for particle shape and size to optimize this gradient and synthesized three types of gradient structures validated by experiments. To maintain this gradient during high-temperature lithium doping, the addition of tantalum oxide was crucial. Tantalum segregates to the surface of crystallites, forming a thin tantalum-rich layer that prevents transition metal interdiffusion and