Ni-doped δ-MnO₂ as a cathode for Zn-ion batteries

Abstract

Among the cathode materials for zinc-ion batteries, manganese oxides have been extensively studied. Thermal decomposition method was adopted to synthesize the Ni-doped δ-MnO2 material, called as NixMn1-xO2. The electrochemical performance and energy storage mechanism of NixMn1-xO2 were studied in 2M ZnSO4 + 0.2M MnSO4 electrolyte. Nickel doping can significantly improve the electrochemical activity of δ-MnO2. Therefore, Ni-doped δ-MnO2 shows better electrochemical cycling performance than δ-MnO2. At 100 mA g−1, NixMn1-xO2 (x=0.2) the specific capacity of 280mAh g−1 in the second circle, and the corresponding voltage platform is 1.36V and 1.23 two discharge voltage platforms. After 100 cycles, the specific capacity of NixMn1-xO2 (x=0.2) still maintain 167 mAh g−1 at a current density of 100 mA g−1. In addition, we also proved that Zn2+ and H+ are co-intercalated into NixMn1-xO2 during the process of charge and discharge and the electrochemical reaction is highly reversible. This research broadens the thinking of exploring ZIBs cathode materials with good specific capacity and cycle performance.

Green Plasma Enhanced Synthesis of Multi-Phase NiMnO3 Cathode for Aqueous Zn-Ion Batteries

“…The electrode that was developed in this work is a step towards the green synthesis of battery devices which can lead to high power and energy density portable energy storage technologies. Where many Zn-ion battery cathodes exhibit pronounced redox peaks in cyclic voltammetry, 13,15,36,37 this work demonstrates a cathode with good pseudocapacitive behaviour in cyclic voltammetry and is used in a Zn-ion battery setup, resulting in battery with strong capacitive cathode behaviour and diffusive anode behaviour for charge storage. The reported nickel-doped Mn oxide 13,38 lead to a higher capacity of a Zn-ion battery than is achieved in this work meaning that more research is needed to unlock the potential presented by our NiMnO 3 electrode.…”

“…[43][44][45] The pursuit of the next generation Zn-ion batteries requires advances in all aspects of the Zn-ion battery cell, including the cathode, anode, electrolyte, OER/HER activity during charging and more. Despite the low performance compared to the state of the art, our NiMnO 3 cathode addresses the issue of low cycle life that is often seen in Zn-ion battery cathodes such as sea-urchin Ni-MnO 2 cathodes 14 which exhibited capacity of 128 mAh g −1 and retention of 62.5% after 30 cycles at 2 mA cm −2 , Ni doped MnO 2 cathode 46 which exhibited capacity of 405 mAh g −1 and retention of 40% after 200 cycles at 1 A/g and Ni doped δ-MnO 2 cathode 15 which exhibited capacity of 255 mAh g −1 and 65.5% retention after 110 cycles at 0.2 A/g. Future research is needed to improve the synthesis method to further increase the surface area to mass loading ratio such that a larger proportion of the electrode material can participate in the charge storage process, as well as improving the synthesis of the nickel doped Mn oxide structures to increase the energy and power output of the electrode.…”

“…14 Ni-doped δ-MnO 2 electrodes which exhibited a specific capacity of 280 mAh g −1 were synthesized due to Zn 2+ and H + reversibly co-intercalating into the NiMnO 2 structure. 15 The reduction and precipitation of nickel-doped Mn-O x is commonly achieved via introduction of reducing agents or the use of methods which are difficult or expensive to achieve. To address this problem, here we propose to use plasma activated water (PAW) with PVA polymer binder to develop an inexpensive approach which is environmentally benign to simultaneously reduce and precipitate nickel-doped Mn-O x .…”

Inside-out regulation of MnO toward fast reaction kinetics in aqueous zinc ion batteries

“…In addition, Ni-MnO and Ni-MnO@rGO show similar curve areas, much larger than the area of MnO, indicating improved capacity. 30 Fig. 3b compares the capacity of the Ni-MnO@rGO electrode after different cycles.…”

“…The more stable cycling performance and higher capacity of Ni-MnO@rGO can be attributed to Ni doping and rGO. 30 The external encapsulation of Ni-MnO by using rGO can remarkably improve the cycling stability. The cycling performance of Ni-MnO@rGO, Ni-MnO and MnO at 0.5 A g À1 clearly proves this trend, as shown in Fig.…”