Silicon-carbon batteries are increasingly appearing in smartphones because they can store more energy than conventional lithium-ion cells without making devices larger. Their adoption by manufacturers including Honor, Oppo, Xiaomi and now Samsung could help deliver genuine two-day battery life, but the technology may involve trade-offs in long-term durability.

Conventional phone batteries typically use graphite anodes, which have been refined for decades and are now a major limit on further performance gains. Silicon can hold substantially more charge, so replacing some graphite in the anode improves capacity; however, silicon expands and contracts during charging cycles, potentially accelerating battery degradation and shortening a phone’s useful lifespan.