Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-020-04243-4 Impact of phase segregation on optical and electrochemical property of BiPO 4 nanostructures for energy storage applications Prakash Chand 1  · Aman Joshi 1  · Vishal Singh 2 Received: 19 June 2020 / Accepted: 12 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract In the present paper, we report the infuence of phase segregation (hexagonal and monoclinic phase) of facile microwave- assisted BPO (BiPO 4 ) nanostructures on optical and electrochemical properties for supercapacitor applications. The XRD patterns reveal pure phase formation of both the samples of BiPO 4 synthesized at 300 °C and 600 °C (JCPDS #15-0766 and JCPDS #43-0637). Phase transition of BiPO 4 from hexagonal to monoclinic phase obtained by sintering the sample (BP600) at 600 °C. The FWHM values of the X-ray difraction peaks observed to decrease with an increase in sintering temperature, which can be ascribed to the enhancement of the crystallite size. The synthesized samples of BiPO 4 are in the nanometer dimension, which also revealed through FESEM examination. FTIR, Raman, and PL spectroscopy also revealed the crystal structure symmetry distinction among the hexagonal and monoclinic BiPO 4 phase. Specifc capacity calculated from GCD (galvanostatic charge and discharge) analysis for BP300 and BP600 samples is 1074 Cg −1 and 451 Cg −1 , correspondingly, at the current density of 1 Ag −1 . The investigation divulges that the phase segregation plays a considerable utility in tuning the electrochemical performance of BiPO 4 nanostructures as active electrode material for next-generation electrochemical capacitors application. 1 Introduction With the rapid progression of the worldwide economies, improved computerization, the shortcoming of fossil fuels, and prompt enhance in population, there is a critical stipulate for competent, sustainable, and clean resources of energy that can substitute traditional energy sources and can also simultaneously accomplish the heightened demand of energy. As a consequence, recently, there has been a budding curiosity in extensive energy density as well as high power storage system [1, 2]. Some of the eminent adequate and realistic technology for galvanic energy transformation and depot are fuel cells, batteries, and electrochemical capaci- tors. Presently, supercapacitor, also labeled ultracapacitors or electrochemical capacitor, have engrossed huge consid- eration in the automobile and consumer electronics indus- tries as they are clean and renewable sources of energy, has great capacitance values, pulse power capability, elongated lifespan charging-discharging cycles (super-long cycle life of over 100,000 cycles), dynamic thermal operating range, immense power density (up to 10 kWkg −1 ). Supercapaci- tors can act as a linking utility for the power and energy gap among established dielectric capacitors (possessing higher power outputs) and batteries/fuel cells (possessing higher energy depot) [3–11]. Although LIB (lithium-ion batter- ies) has high energy density storage, they distribute only limited power upon discharge. Supercapacitors can replace the batteries and are suitable for those applications where instant power is needed [12, 13]. Supercapacitors furnish a 100 to 1000 times superior power per unit volume and can also accumulate a large charge, leading to abounding power ratings than rechargeable batteries [4, 14]. Supercapacitor could be classifed into three forms: EDLC (electrochemical double layer), pseudo capacitor, and hybrid types, which is designed via fusion of EDLC and pseudo capacitor. EDLCs type supercapacitor, utilize electrostatic charge separa- tion for energy storage. EDLCs store energy electrostati- cally at the junction between the electrolyte and the elec- trode surface [15]. Whereas, pseudocapacitors store energy electrochemically and are established on reversible oxida- tion–reduction reactions at the interfacial among electrode * Prakash Chand prakash@nitkkr.ac.in 1 Department of Physics, National Institute of Technology, Kurukshetra 136119, India 2 Materials Science & Engineering, National Institute of Technology, Hamirpur 177005, India