Nanosilicon anodes for high performance rechargeable batteries

Modified Stoney Model and Optimization of Electrode Structure Based on Stress Characteristics

“…The bilayer stress comprises two components: the first for axial compressive (or tensile) stress in the active layer (or current collector) and the second for bending stress distributed along the thickness of the bilayer electrode due to changed coordinates � z a and � z c . Equation (9) shows that the bilayer stress directly depends on the thickness ratio l, modulus ratio m, and mismatch strain β� c. Therefore, a different l or m will inevitably cause different stress responses, even for the same β� c. This implies that electrochemicalinduced softening and stiffening have a significant effect on the stress response. To describe the relationship between bilayer stress and mismatch strain and the affected extent on stress by l and m, the stress factor G is defined as:…”

“…Electrochemical research has demonstrated that various treatments of electrodes significantly improve the cycle performance, including the use of nanostructures, [7] a coreshell structure, [8] surface coatings, [9] and electrode thickness [10] on active layer, and use of a foams or flexible current collector. [11,12] In cross-disciplinary research in electrochemistry and mechanics, experiments have confirmed that these strategies essentially mitigate electrochemically induced expansion and change the stress state of electrodes to a certain extent; [13][14][15][16] conversely, stress affects the diffusion and kinetics, [17][18][19] and capacity [20] of a battery.…”

“…And in this method the calculated stress by Stoney equation ignores bending stress and, more importantly, ignores the already confirmed concentration-dependent elastic modulus of the active material. [9,36] These non-considerations necessarily affect the overall stress analysis of electrodes in an electrochemical process. Xie et al recently characterized the stresses of an active material and a current collector in a Si composite electrode using a combination of bending deformation measured by a simple optical method and a proposed stress model that considered variable elastic modulus with capacity.…”

New functional material: spark plasma sintered Si/SiO2 nanoparticles – fabrication and properties

“…An ensemble of nanostructured silicon particles embedded into an SiO 2 host has been the subject of intensive research over the last two decades. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The main motivation for research in this eld is the fabrication of silicon-based light emitters, which utilize the reduced dimension connement effect to overcome indirect bandgap limitations for radiative recombination in Si. 2,11,12,15 It is also worth citing some other applications of Si nanoparticles, such as photovoltaic cells, 14,21,22 batteries, 23,24 etc.…”

“…3,5,6,8,10,13,[16][17][18] Thermal annealing of SiO x layers fabricated by various chemical deposition techniques was also used. 4,14,19 Considering Si nanoparticle powders, one could mention milling techniques and plasma torches; however, these methods are not oen used for applications in optics. [23][24][25][26] In the present paper, we report on the results of fabricating a bulk material consisting of Si nanoclusters in an SiO 2 matrix.…”