New battery design unlocks simpler, cheaper zinc-based power storage
Researchers have solved a decades-old incompatibility problem in zinc-manganese batteries, paving the way for cheaper, simpler energy storage that rivals lithium-ion performance. The breakthrough uses a clever two-layer electrolyte design to let each electrode operate independently, potentially cutting manufacturing costs and opening new markets for stationary power and portable devices.
Originaltitel: Dissimilar Electrolyte Decouples Zn and MnO2 Redox Chemistry Enabling Dual-Electrode-Free Lean-Electrolyte Batteries
<p>Dual-electrode-free Zn-MnO2 batteries offer exceptionally high theoretical energy density (616 mAh g-1 at 2 V) and simplified manufacturing, yet their practical use is hampered by low Coulombic efficiency (CE) and unstable cycling, arising from the intrinsic incompatibility of Zn and MnO2 redox chemistries. Previous studies employing preloaded Zn and excess electrolyte obscure this incompatibility. Herein, we design a dissimilar electrolyte architecture to decouple Zn plating-stripping from MnO2 deposition-dissolution, fundamentally addressing their incompatibility. The architecture integrates two distinct gels, wherein a self-assembled nanometer-thin water layer functions as a "soft wall" for selective ion transport due to binding energy differences at the gel/water interface. Further, the screening effect induced by the discrepancy in ionic conductivity across the junction is investigated for the first time, offering new insights into ion transport in heterogeneous electrolytes. This strategy enables a dual-electrode-free lean-electrolyte Zn-MnO2 cell with areal and volumetric energy densities of 3.1 mWh cm-2 and 25.8 Wh L-1, and a power density of 24.1 mW cm-2 at 2 mAh cm-2. The cell also achieves an average CE of 91% at 1mAh cm-2 cycling. Moreover, the dual-electrode-free configuration readily integrates with diverse current collectors, extending the concept to flexible and stretchable batteries for wearable electronics, soft robotics, and beyond.</p>