Carbon Nanotube-Functionalized Surface-Assisted Growth of Cobalt Phosphate Nanodots: A Highly Stable and Bendable All-Solid-State Symmetric Supercapacitor
Akanksha Agarwal, Sutripto Majumder, Babasaheb R. Sankapal
Abstract
Phosphate compounds have sparked the scenario and emerged as new electrode materials for energy storage systems due to their high redox chemistry. However, these materials suffer from sluggish electrode kinetics and low utilization efficiency, resulting in subpar storage performance. Herein, we report a facile and cost-efficient chemical method for directly anchoring cobalt phosphate (Co2P2O7) nanodots onto multiwalled carbon nanotubes (MWCNT) to design a multifaceted Co2P2O7/MWCNT core–shell-type structure. The as-designed heterostructure with dual charge storage profiles provides a high level of intercomponent synergy, promoting the occurrence of extrinsic pseudocapacitance. By ensuring continuous charge transfer pathways for sustained electrochemical performance, MWCNT support excellent electronic conductivity with good resilience to the dependability of Co2P2O7, resulting in exceptional mechanical robustness. The Co2P2O7/MWCNT exhibits significantly improved specific capacity and rate performance, outperforming pristine MWCNT. The assembled flexible all-solid-state symmetric supercapacitor device with a Co2P2O7/MWCNT electrode and a freestanding PVA-KOH electrolyte membrane possesses an exceptional specific energy of 57.3 W h kg–1 with good power output. Moreover, as a result of the well-interwoven all-solid-state assembly, the device displays commendable cyclic stability with a retention of 105% even at 5000 cycles, along with good deformable compatibility. The lighting up of 21 red light-emitting diodes provides practical evidence for the as-fabricated device’s applicability in current miniaturized electronics.