Elevated energy density and cycle stability of α-Mn2O3 3D-microspheres with addition of neodymium dopant for pouch-type hybrid supercapacitors

Abstract Synthesis of high energy density and long durability electrode materials are huge urgency for futuristic hybrid supercapacitors (HSCs). In the present work, self-assembled three-dimensional (3D)-mesoporous regimented pristine and neodymium (Nd) doped α-Mn2O3 microspheres (MSs) are prepared by simple hydrothermal method. Due to uniform morphology, presence of oxygen vacancies, mesoporous robust structure, and optimum doping (Nd5%-doped Mn2O3 3D-MSs) offers a high specific capacitance of 862.14 F g−1 (431.07 C g−1) at 0.5 A g−1 with superior cycling retention of 97.30% after 2,000 cycles. Additionally, a pouch-type HSC device is fabricated using Nd5%-Mn2O3 3D-MSs as a battery-type positive electrode and activated carbon (AC) as a capacitive-type negative electrode. The fabricated device delivers a maximum energy density of 32.26 Wh kg−1 at a power density of 800 W kg−1 with superior cyclic retention and exhibit a little loss of 4.56% after 10,000 cycles. This superior performance is due to robust microstructures that can alleviate swelling and shrinking of active material at cycling test. Two pouch-type HSCs are connected in series to power light-emitting diodes (LEDs) for real-time applicability. Overall, this study demonstrates that rational doping, porous architecture, oxygen vacancies, and robust micro-nano structure greatly assist to achieve high energy density as well as long life HSCs devices.