The secret to making batteries last 20,000 cycles is actually letting the cathode dissolve in water.
April 15, 2026
Original Paper
Pyridinic nitrogen enables azo compound with capacity-stability trade-off for high-energy aqueous zinc batteries
SSRN · 6569666
The Takeaway
In battery engineering, solubility is usually the enemy—if the cathode dissolves, the battery fails. This research flips that assumption by developing a material (AZPY) that is 'dissolved but more stable.' The dissolved particles form a protective hydrogen-bonding network in the aqueous electrolyte, preventing the typical degradation that kills zinc batteries. This counter-intuitive property allows for a massive 20,000-cycle life, paving the way for ultra-durable, low-cost energy storage. It's a complete shift in how we think about electrolyte-cathode interaction.
From the abstract
Azo compounds with N=N groups have been employed in rechargeable aqueous zinc-ion batteries owing to high theoretical capacity derived from two‐electron redox reaction. However, their cycling stability remains inadequate due to the high solubility of organic small molecules and discharge products in aqueous electrolytes. Herein, we designed π-conjugated azo small molecule (azobenzene (AZB) and 4,4'-azopyridine (AZPY)) with stable two-electron transfer but slight differences in aromatic moie