Nanoarchitectonics of interstitial oxygen and Jahn-Teller distortion to enhance electrochemical performance of CuMnO2: symmetric coin-cell

Abstract

In this work, influence of interstitial oxygen and Jahn-Teller distortion of Mn ions, tuned by varying alkali concentration during hydrothermal reaction, on the charge storage capacity of monoclinic CuMnO2 nanoplate electrodes has been investigated, followed by tuning them to improve the capacitance. CuMnO2 nanoplates, prepared at optimum pH, exhibits high specific capacity ∼ 120 F.g− 1 at 2 mVs− 1 scan rate using environment friendly electrolyte Na2SO4. Symmetric coin-cell, prepared with CuMnO2 nanoplates, exhibits specific capacitance ∼ 86.5 Fg− 1 at 2 mVs− 1 scan rate (∼ 71.2 Fg− 1 at 0.35 A/g), energy density ∼ 14.2 Wh/kg and power density ∼ 333.3 W/kg which make it a promising candidate for supercapacitor applications. It has been found that the charge transfer mechanism across electrode – electrolyte interface is governed by Marcus’s mechanism, wherein Jahn-Teller distortion plays most predominant role. Our theoretical analysis on the basis of density functional theory, provides better insight about the influence of interstitial oxygen on storage capacity. Herein, we have identified that interstitial oxygen tunes electron density on Mn³⁺ sites which in consequence facilitates specific capacitance. Our studies clearly reveal that CuMnO2 may be a potential, biocompatible pseudocapacitive energy storage material.

Full text

Applied Physics A (2025) 131:8
https://doi.org/10.1007/s00339-024-08116-z
fuels. In the frontier of energy storage application, devel-
opment of advanced electrochemical energy storage prin-
ciples [1, 2], especially rechargeable battery [3] etc. play
most prominent role [4, 5]. Among them, supercapacitors
have particularly gained attention, for automotive and por-
table energy storage systems due to high power density
[6], fast charge-discharge rate, and wide range of operating
temperature, long life cycles [7] and being environmentally
compatible [8–11]. Commonly, supercapacitors work on
two dierent principles of charge storage mechanism and
accordingly they are classied into electric double layer
capacitor (EDLC) and pseudocapacitor. EDLC utilizes elec-
trostatic adsorption/desorption to store charge and exhibits
higher power density. In contrast, pseudocapacitor utilizes
reversible Faradaic reaction and correspondences higher
energy density [12, 13]. During recent past, much research
eorts were given to design transition metal oxides (TMOs)
[14], hydroxide, sulphide, conducting polymer based pseu-
docapacitor for improved electrochemical performances,
wherein TMOs exhibit much better performance in terms
of durability, cost, bio-compatibility etc [15–18]. However,
1 Introduction
Over the past few years, requirement of sustainable tech-
nology for clean, renewable energy generation and storage
is increasing rapidly because of rapid depletion of fossil
Chandan Kumar Ghosh
chandu_ju@yahoo.co.in
1 School of Materials Science and Nanotechnology, Jadavpur
University, Jadavpur, Kolkata 700032, India
2 Department of Physics, Jadavpur University,
Jadavpur, Kolkata 700032, India
3 Department of Instrumentation Science, Jadavpur University,
Kolkata 700032, India
4 Center of Excellence for Research in Engineering Materials
(CEREM), Deanship of Scientic Research, College of
Engineering, King Saud University, Riyadh
11421, Saudi Arabia
5 Advanced Mechanical and Materials Characterization
Division, CSIR-Central Glass and Ceramic Research
Institute, Kolkata 700032, India
Abstract
In this work, inuence of interstitial oxygen and Jahn-Teller distortion of Mn ions, tuned by varying alkali concentra-
tion during hydrothermal reaction, on the charge storage capacity of monoclinic CuMnO2 nanoplate electrodes has been
investigated, followed by tuning them to improve the capacitance. CuMnO2 nanoplates, prepared at optimum pH, exhibits
high specic capacity ∼ 120 F.g− 1 at 2 mVs− 1 scan rate using environment friendly electrolyte Na2SO4. Symmetric coin-
cell, prepared with CuMnO2 nanoplates, exhibits specic capacitance ∼ 86.5 Fg− 1 at 2 mVs− 1 scan rate (∼ 71.2 Fg− 1 at
0.35 A/g), energy density ∼ 14.2 Wh/kg and power density ∼ 333.3 W/kg which make it a promising candidate for super-
capacitor applications. It has been found that the charge transfer mechanism across electrode – electrolyte interface is
governed by Marcus’s mechanism, wherein Jahn-Teller distortion plays most predominant role. Our theoretical analysis on
the basis of density functional theory, provides better insight about the inuence of interstitial oxygen on storage capacity.
Herein, we have identied that interstitial oxygen tunes electron density on Mn3+ sites which in consequence facilitates
specic capacitance. Our studies clearly reveal that CuMnO2 may be a potential, biocompatible pseudocapacitive energy
storage material.
Keywords Delafossite · Hydrothermal · Jahn – Teller · Defects · Coin-cell
Received: 25 June 2024 / Accepted: 20 November 2024 / Published online: 6 December 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Nanoarchitectonics of interstitial oxygen and Jahn-Teller distortion to
enhance electrochemical performance of CuMnO2: symmetric coin-cell
RaushanKabir1,2· RoshniBegum1· Kumar RiddhimanSahoo1· SudiptaGoswami1· Sachindra NathDas3·
Mohammad RezaulKarim4· DiptenBhattacharya5· SaikatSeth2· Chandan KumarGhosh1
1 3
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