MXene-Integrated Perylene Anode with Ultra-Stable and Fast Ammonium-Ion Storage for Aqueous Micro Batteries

The aqueous micro batteries (AMBs) are expected to be one of the most promising micro energy storage devices for its safe operation and cost-effectiveness. However, the performance of the AMBs is not satisfactory, which is attributed to strong interaction between metal ions and the electrode materials. Here, the first AMBs are developed with NH₄ ⁺ as charge carrier. More importantly, to solve the low conductivity and the dissolution during the NH₄ ⁺ intercalation/extraction problem of perylene material represented by perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), the Ti₃ C₂ T_x MXene with high conductivity and polar surface terminals is introduced as a conductive skeleton (PTCDA/Ti₃ C₂ T_x MXene). Benefitting from this, the PTCDA/Ti₃ C₂ T_x MXene electrodes exhibit ultra-high cycle life and rate capability (74.31% after 10 000 galvanostatic chargedischarge (GCD) cycles, and 91.67 mAh g^-1 at 15.0 A g^-1 , i.e., capacity retention of 45.2% for a 30-fold increase in current density). More significantly, the AMBs with NH₄ ⁺ as charge carrier and PTCDA/Ti₃ C₂ T_x MXene anode provide excellent energy density and power density, cycle life, and flexibility. This work will provide strategy for the development of NH₄ ⁺ storage materials and the design of AMBs.