Fig. 1. (a) Schematic diagram of the metal-water triple point cell system (TEC: Thermoelectric cooler, Pt: Platinum resistance, NTC: Negative temperature coefficient thermistor); (b) Miniaturized metal-water triple point cell

Fig. 2. Reproduction of the metal-water triple point temperature in a metal bottle. (a) The spontaneous phase transition experiment of the metal triple point bottle （The red and black lines represent the changes in temperature inside and outside the bottle, respectively）; (b) Temperature fluctuations inside the metal-water triple point bottle after stabilization