Polyaniline/MnO2-PLA composites: a high-performance and eco-friendly electrode for supercapacitors

Polyaniline (PANI) has wide application prospects in energy storage for environmental protection. In this paper, a binary composite material consisting of manganese dioxide (MnO₂) and PANI was synthesized and then combined with the degradable polymer polylactic acid (PLA) to prepare an environmentally degradable electrode. The optimal amount of MnO₂ was determined, and the electrochemical performance of the composite material was systematically studied in three different electrolytes including H₂SO₄, ZnSO₄, and Na₂SO₄. The PANI/MnO₂ composite material (PANI/MnO₂-1) exhibits good charging-discharging behavior with a specific capacitance of 605 F/g in 0.5 M H₂SO₄, 43% increases compared to pure PANI. It indicates that the introduction of MnO₂ enhance the charge storage capacity of the electrode. Additionally, the PANI/MnO₂-1 electrode retains 71% of capacitance after 1000 cycles in ZnSO₄ electrolyte, demonstrating good zinc-ion storage performance. Furthermore, the PANI/MnO₂–2-1-PLA electrode, fabricated using PLA as a binder, exhibited a specific capacitance of 416 F/g in 0.5 M H₂SO₄. Notably, it retained 93% of its maximum capacitance after being soaked in the acidic electrolyte for 60 days, demonstrating good short-term electrochemical stability. These results suggest that incorporating biodegradable PLA as a binder does not significantly compromise performance and offers a promising strategy for developing environmentally friendly supercapacitor electrodes.