Electrode materials for lithium ion batteries

Electrode Materials for Lithium Ion Batteries

Introduction and Motivation
Conversion and storage of „green energy“ exhibits nowadays one of the most challenging tasks. Crystalline semiconductornanostructures are promising candidates for future electronic devices due to their high surface to volume ratio, the ability to uptake significant mechanical strain and their unique transportproperties. Next-generation electrodes are expected to achieve both long term stability and high reversible capacity. Different nanostructured semiconductors were synthesized and investigated as potentialanode materials for lithium-ion batteries. The direct deposition on copper foil improves the adhesion to the current collector leading to a higher carrier transportation. Aditionally, thefunctionalization of the nanomaterials shows major improvements concerning stability and capacity as it is shown in the electrochemical measurements.

0D-Nanostructures: Tin @Hollow Graphite Spheres bySolvolthermal-synthesis
★ ★ ★ ★ ★ ★-- Sn -- SnO2 ★★ ★

  

Sn NPs encapsulated in hollow carbon spheres (HSC@Sn).

Fractal-like architectures (Sn@HSC)

1D/3D-Nanostructures: Tin Oxide and Germaniumnanowires via Chemical Vapor Deposition
Au Sputtering 2nd CVD

SnO2@SnO2

Ge NWs

Sn(OtBu)4
Advantages: 1. Increase of the active mass 2. SnO2 theoretical capacity = 790mAhg-1 PECVD

GeCp22nd CVD

C@SnO2

SnO2

Ge

Ge@Si

Advantages:
1. 2. 3.
e-

1. Better adhesion to the substrate 2. Strain relaxation induced by volume changes 3. Improved conductivity and electronictranspor tproperties

Advantages:

1. High theoretical capacities: Germanium = 1600mAhg-1 Silicon = 4200 mAhg-1 2. Ultra fast and low temperature CVD

3D-Nanostructures: Electrospinning of TinOxide Nanofibers
Sn(OtBu)4 PVP EtOH Sol Acid

Gel

Calcination Furnace under N2 at 850°C

Acknowledgement
Authors thank Fraunhofer ISC for electrochemical characterizations and Prof. Dr. W....