Nitrogen, Phosphorus, and Sulfur Tri-doped Carbon A Coated NiCo2Se4 Needle Arrays Grown on Carbon Cloth as Binder-free Anode for Potassium-Ion Batteries

Abstract

Bimetallic selenides are considered to be the promising high-capacity anode materials for potassium ion batteries (PIBs). However, the dramatic volume fluctuation of K+ ions and pulverization during cycling still limit their practical application in PIBs. Herein, the nitrogen, phosphorus, and sulfur tri-doped carbon (SPNC)-coated bimetallic NiCo2Se4 needle arrays grown on carbon cloth (NiCo2Se4⊂SPNC/CC) prepared as a binder-free anode for PIBs. The polyphosphazene (PSZ) was used as ingenious heteroatoms doping carbon source. The coated SPNC layer derived from the PSZ on the surfaces of NiCo2Se4 needle arrays not only effectively alleviate the volume expansion of NiCo2Se4 but also provide abundant active sites for the storage of K+ ions. As the PIB anode, the NiCo2Se4⊂SPNC/CC could deliver a high reversible capacity of 880.9 mA h g−1 at a current density of 0.1 A g−1. After 500 cycles, the NiCo2Se4⊂SPNC/CC anode still maintains a high reversible capacity of 268.1 mA h·g−1 at a current density of 0.5 A g−1.

Conversion mechanism of NiCo 2Se 4 nanotube sphere anodes for potassium-ion batteries

“…In succeeding cycles, the main reduction peak at 0.51 V in the 1st potassiation cycle divided into two at 0.32 and 0.80 V through the electrochemical reactions of Co 3 Se 4 and Ni 3 Se 4 . This finding is supported by similar results in previous studies [25,26] . In subsequent cycles, the redox reactions are associated with the reversible conversion between the metals (Ni and Co) and selenides (NiSe x and CoSe x ), according to the following equations:…”

“…However, only a few TMSs have thus far been explored for PIB anodes, and their K + storage mechanisms have yet to be unveiled. Among these, NiCo 2 Se 4 -a conversion-based anode material that was previously studied for sodium storage, supercapacitors, and electrocatalysts [17][18][19] -presents [26][27][28][29][30][31][32][33][34][35][36][37][38] .…”

Bimetallic-based composites for potassium-ion storage: challenges and perspectives

“…82 Lastly, non- metallic doping improves material stability, leading to excellent electrochemical properties. 56 Doping with non-metallic ions can yield different types of compounds depending on the dopant type, doping method, doping amount, and dopant location.…”

“…The active metal in ABXs participates in the reaction, while the inert metal maintains the stability of the structure, alleviating the bulk expansion problem faced by single metal compounds. 52 Compared to single metal compounds, ABXs have many advantages: 53 (a) multiple charge storage mechanisms (such as intercalation/deintercalation reaction, conversion reaction, alloying reaction, and synergism of multiple storage mechanisms) for more efficient storage of K + ; 54 (b) extended working voltage window for high energy density; 55 (c) provide more redox active sites for higher pseudocapacitance; 56 (d) adjust different metal proportions to obtain rich multidimensional structures; (e) metal ions (A and B) with multiple valence states and different redox potentials lead to efficient Faraday redox reactions while facilitating electron transport during charging/discharging. 57 ABXs have severally been reported as promising high-performance electrode materials, but few reports have provided in-depth and comprehensive summaries of them in recent years, prompting us to summarize the latest research and focus on better understanding the properties of ABXs.…”

Emerging carbon-based flexible anodes for potassium-ion batteries: Progress and opportunities

“…Meanwhile, a tightly bind of support and active electrode materials are thought to accommodate the volumetric change and the decomposition of electrode materials during battery applications. In flexible electrodes, the supports usually include the commercial carbon fiber cloth with three-dimensional structures, good flexibility, and good conductivity ( Fan et al, 2022 ), carbon nanotubes with excellent physical, chemical, and mechanical properties ( Zhao et al, 2017 ), nickel foam with three-dimensional uniform network structures ( Huang et al, 2014 ), and graphene with a large surface area, high conductivity ( Wu et al, 2019a ), and so on.…”