realme has once again pushed the boundaries of smartphone innovation, showcasing two futuristic concepts at its 828 Fan Festival 2025 online event – a smartphone with a massive 15,000 mAh battery and the world’s first “AC phone”, dubbed the realme Chill Fan phone.
The highlight was undoubtedly the 15,000 mAh battery phone, which realme claims is 42% slimmer at just 8.89mm and 68% lighter compared to a power bank of the same capacity. To achieve this, the company has developed a new all-silicon content anode battery, with 25% silicon content, making it the world’s first of its kind. Combined with a record-breaking energy density of 1200 Wh/L, realme managed to pack extraordinary capacity into a slimmer smartphone body.
The main board of the device has been slimmed down to a world-record 23.4mm, while advanced lamination technology keeps the battery itself at just 6.48mm. Despite its sheer size, the battery promises impressive efficiency – offering up to 18.45 hours of video shooting, 30 hours of gaming, or 50 hours of video playback on a single charge. realme says a full charge can deliver up to 5.18 days of use and as much as three months of standby time in airplane mode.
Beyond the battery, realme confirmed other specifications, including a 6.7-inch OLED display, MediaTek Dimensity 7300 SoC, 12 GB RAM, 256 GB storage, and 80W SuperVOOC fast charging. The device draws similarities to realme’s 10,000 mAh concept phone revealed earlier this year, hinting at a possible roadmap for commercialization.
Alongside this, realme introduced the Chill Fan phone, a bold experiment in mobile cooling technology. Marketed as the world’s first “AC phone”, it features 7,700 mm² VC cooling combined with fan-assisted heat dissipation and a thermoelectric cooler (TEC) module. The TEC, built with a miniature semiconductor, is said to reduce the phone’s core temperature by up to 6ºC – two to three times more effective than traditional vapor chambers.
Adding a visual twist, realme has designed the IceSense Ultra back panel to shift colors from white to blue as the temperature drops from 45°C to 38°C. Tested in a popular anime strategy game running at full FPS, the Chill Fan phone demonstrated a temperature reduction of up to 6.2ºC.
While the Chill Fan phone’s mass production timeline remains uncertain, realme’s 10,000 mAh battery phone is reportedly set to arrive in the market as early as 2026. The 15,000 mAh concept, however, may take longer to materialize.
