China develops water battery with 120,000-cycle lifespan

Researchers in China built an aqueous battery using a neutral electrolyte of magnesium or calcium salts and a specially designed organic polymer. The cell survived 120,000 charge-discharge cycles without failing, retaining about 72% capacity in the magnesium chloride version — equivalent to roughly 329 years of daily cycling.

• Battery survived 120,000 charge-discharge cycles without failure
• Magnesium chloride version retained about 72% of capacity
• 120,000 cycles equal roughly 329 years of daily use
• Neutral magnesium and calcium salt electrolyte cuts side reactions