Construction of a 12‐Phosphomolybdate‐based Coordination Polymer@Crumpled Graphene Balls Composite as Anode for Lithium Batteries

Abstract

To address the poor electronic conductivity and easily dissolved in electrolyte of polyoxometalates (POMs), and considering the high electrical conductivity and configuration advantages of crumpled graphene balls (CGBs), herein, a series of POM‐based coordination polymers [Cu(pyttz)2]PMo12@CGB (n, n=1, 2, 3) were successfully synthesized, and electrochemical lithium storage performance and lithium ion diffusion kinetics were comprehensively investigated. Galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) study confirm that [Cu(pyttz)2]PMo12@CGB (n, n=1, 2, 3) integrates the advantage of high electronic conductivity of CGB and excellent Li+ migration kinetics of POMs, which greatly ameliorates the electrochemical performances of POMs, among [Cu(pyttz)2]PMo12@CGB (2) exhibits an excellent reversible specific capacity of around 941.4 mA h g−1 at 0.1 A g−1 after 150 cycles and admirable rate performance. This work will promote the development of POMCP anodes, thus fulfilling their potential in high‐performance LIBs.

Diphosphorus Center Derived from Polyoxometalate for High-Energy Lithium Storage of MXene Nanosheets

“…The reaction current density, especially the oxidation current density, increases with the increase in the amount of PMA (as shown in Figure f–h), which is in accordance with the results of the charge and discharge curves. The reduction peak at 1.02 V is assigned to the lithiation process in the MoO 6 octahedron of Keggin structure polyoxometalate, and the oxidation peak at 1.44 V is assigned to the delithiation process. , The reduction peak at 0.73 V is assigned to the lithiation and conversion reaction of MoP 2 → Li 3 P, and the oxidation peak at 0.93 V corresponds to the delithiation of Li 3 P → Li x MoP 2 . In the second CV curve, the reaction current density of redox peaks for 0.05PMA@Ti 3 C 2 T x decreases, which is attributed to the capacity loss from an irreversible side reaction and the slight structure degradation.…”

“…In addition, the construction of heterostructures is an effective strategy to regulate the properties of two-dimensional materials. , The transition metal phosphides exhibit good lithium storage capacity owing to excellent conductivity, multielectron transfer reaction, and lower lithiation/delithiation potential. , Polyoxometalates are three-dimensional clusters composed of transition metal oxyanions, exhibiting promising energy storage performance due to high theoretical capacity, electron and proton transfer abilities, and reactive lattice oxygen. − However, the energy storage abilities are restricted by worse lithium-ion migration and smaller specific surface areas . Polyoxometalates can be decomposed into transition metal oxides and phosphides during the calcining process, which will further improve the electronic and ionic conductivity.…”