PlumX Metrics
Embed PlumX Metrics

Enhanced high rate capability of Li intercalation in planar and edge defect-rich MoS nanosheets

Nanoscale, ISSN: 2040-3372, Vol: 11, Issue: 18, Page: 8882-8897
2019
  • 24
    Citations
  • 0
    Usage
  • 25
    Captures
  • 0
    Mentions
  • 7
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

Article Description

(i) Edge and planar defect-rich and (ii) defect-suppressed MoS nanosheets are fabricated by controlled annealing of wet-chemically processed precursors. Wrinkles, folds, bends, and tears lead to the introduction of severe defects in MoS nanosheets. These defects are suppressed and highly crystalline MoS nanosheets are obtained upon high-temperature annealing. The influence of defects on the electrochemical properties, particularly rate capability and cycling stability, in the Li intercalation regime (1 V to 3 V vs. Li/Li ) and conversion regime (10 mV to 3 V vs. Li/Li ) are investigated. In the intercalation regime, the initial Li intake (x in Li MoS ) for defect-rich nanosheets is larger (x ≈ 1.6) as compared to that in defect-suppressed MoS (x ≈ 1.2). Although the reversible initial capacity of all the anodes is nearly the same (x ≈ 0.9) at 0.05C rate, defect-rich MoS exhibits high rate capability (>40 mA h g at 40C or 26.8 A g ). When cycled at 10C (6.7 A g ) for 1000 cycles, 75% capacity retention is observed. High rate capability can be attributed to the defect-rich nature of MoS , providing faster access to lithium intercalation by a shortened diffusion length facilitated by Li adsorption at the defect sites. The defect-rich nanosheets exhibit a power density of ∼20% more than that of defect-suppressed nanosheets. For the first time, MoS /Li cells with a high power density of 10-40 kW kg in the intercalation regime have been realized. In the conversion regime, defect-rich and defect-suppressed MoS exhibit initial lithiation capacities of ∼1000 and ∼840 mA h g , respectively. Defect-rich MoS had a capacity of ∼800 mA h g at 0.1C (67 mA g ), whereas defect-suppressed MoS had a capacity of only ∼80 mA h g at the same current rate. Capacity retention of 78% was observed for defect-rich MoS with a reversible capacity of 591 mA h g when cycled at 0.1C (67 mA g ) for 100 cycles. Despite having a lower energy density in the intercalation regime, the power density of defect-rich MoS in the intercalation regime is significantly larger (by three orders of magnitude) as compared to that of defect-suppressed MoS in the conversion regime. Defect-rich MoS nanosheets are promising for high-rate-capability applications when operated in the intercalation regime.

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know