Electrochemical Mechanism Investigation of Cu₂MoS₄ Hollow Nanospheres for Fast and Stable Sodium Ion Storage

Abstract

Sodium ion batteries (SIBs) are promising alternatives to lithium ion batteries with advantages of cost effectiveness. Metal sulfides as emerging SIB anodes have relatively high electronic conductivity and high theoretical capacity, however, large volume change during electrochemical testing often leads to unsatisfactory electrochemical performance. Herein bimetallic sulfide Cu 2 MoS 4 (CMS) with layered crystal structures are prepared with glucose addition (CMS1), resulting in the formation of hollow nanospheres that endow large interlayer spacing, benefitting the rate performance and cycling stability. The electrochemical mechanisms of CMS1 are investigated using ex situ X-ray photoelectron spectroscopy and in situ X-ray absorption spectroscopy, revealing the conversion-based mechanism in carbonate electrolyte and intercalation-based mechanism in ether-electrolyte, thus allowing fast and reversible Na + storage. With further introduction of reduced graphene oxide (rGO), CMS1-rGO composites are obtained, maintaining the hollow structure of CMS1. CMS1-rGO delivers excellent rate performance (258 mAh g −1 at 50 mA g −1 and 131.9 mAh g −1 at 5000 mA g −1 ) and notably enhanced cycling stability (95.6% after 2000 cycles). A full cell SIB is assembled by coupling CMS1-rGO with Na 3 V 2 (PO 4 ) 3 -based cathode, delivering excellent cycling stability (75.5% after 500 cycles). The excellent rate performance and cycling stability emphasize the advantage of CMS1-rGO toward advanced SIB full cells assembly.

Rational Design of Core@shell Structured CoSx@Cu2MoS4 Hybridized MoS2/N,S‐Codoped Graphene as Advanced Electrocatalyst for Water Splitting and Zn‐Air Battery

“…HR‐TEM image in Figure h demonstrated the formation of a core@shell structure for NPs, in which the core and shell portion showed dark and gray color, respectively. Figure i and Figure S6 in the Supporting Information clearly identified the lattice fringes of CoS x ‐core with spacings of 0.20 and 0.28 nm, consistent with d(111) and d(200) crystal planes of Co and CoS 2 phases, respectively, while a lattice spacing of 0.51 nm was suitable with d(002) crystal plane of Cu 2 MoS 4 ‐shell …”

Cu2MoS4 Nanotubes as a Cathode Material for Rechargeable Magnesium‐ion Battery

“…The powder XRD analysis further confirms the generation of pure I‐phase Cu 2 MoS 4 wherein patterns of impurity phases like Cu 2 O, MoO 3 and MoS 2 are not found (Figure d) . Raman analysis using a green laser 532 nm excitation reveals characteristic vibration modes within the Cu 2 MoS 4 molecule (Figure S4) .…”

“…investigated on the use of a Cu 2 MoS 4 hollow nanospheres for fast and stable sodium‐ion battery . Capacities of 258 mAh.g −1 at 50 mA.g −1 and 131.9 mAh.g −1 at 5000 mA.g −1 together with a remarkable stability of 95.6 % after 2000 charge/discharge cycles were reported . To the best of our knowledge, the use of Cu 2 MoS 4 cathode material within a MIB has been not investigated yet.…”

Encapsulation of MnS Nanocrystals into N, S-Co-doped Carbon as Anode Material for Full Cell Sodium-Ion Capacitors

“…Thus, it is important and urgent to explore an alternative energy storage system. Recently, research interests on sodium-ion batteries (SIBs) have rapidly grown not only due to the earth-abundant and evenly distributed sodium resource, but also due to its similar electrochemical behavior to lithium [8][9][10][11][12]. Unfortunately, similar to LIBs, SIBs are also limited by poor power density and relatively inferior cycling stability.…”