Wireless charging uses electromagnetic induction to transfer power without a cable. Qi is the open standard (5–15W typical); Apple's MagSafe is a magnetic Qi extension (15W).
Common wireless charging tiers: 5–7.5W: standard Qi (older iPhones, basic Android). 10–15W: enhanced Qi (most flagships). 15W MagSafe: Apple iPhone 12+, magnetic alignment. 50W proprietary (Xiaomi, OnePlus): requires brand-specific charger.
Qi2 (2024): adopts Apple's magnetic alignment as a universal standard, supports up to 15W with broader compatibility.
Wireless charging is ~70–80% efficient (vs 95%+ wired) — slightly more heat and battery wear over years. Convenient but slower than wired fast charging.