A low-cost and high performance ball-milled Si-based negative electrode for high-energy Li-ion batteries

Abstract

International audienceA Si-based anode with improved performance can be achieved using high-energy ball-milling as a cheap and easy process to produce Si powders prepared from a coarse-grained material. Ball-milled powders present all the advantages of nanometric Si powders, but not the drawbacks. Milled powders are nanostructured with micrometric agglomerates (median size [similar]10 μm), made of submicrometric cold-welded particles with a crystallite size of [similar]10 nm. The micrometric particle size provides handling and non-toxicity advantages compared to nanometric powders, as well as four times higher tap density. The nanostructuration is assumed to provide a shortened Li+ diffusion path, a fast Li+ diffusion path along grain boundaries and a smoother phase transition upon cycling. Compared to non-milled 1-5 μm powders, the improved performance of nanostructured milled Si powders is linked to a strong lowering of particle disconnection at each charge, while the irreversibility due to SEI formation remains unchanged. An electrode prepared in acidic conditions with the CMC binder achieves 600 cycles at more than 1170 mA h per gram of the milled Si-based electrode, in an electrolyte containing FEC/VC SEI-forming additives, with a coulombic efficiency above 99%, compared to less than 100 cycles at the same capacity for an electrode containing nanometric Si powder

Rapid mechanochemical synthesis of amorphous alloys

“…For instance, Gauthier et al ball milled Si powder using conventional SPEX milling conditions with large steel balls and only achieved an average grain size of 10 nm after 20 hours milling time. 9 Here, our optimized SPEX milling method results in an average Si grain size that is less than half of this in only 4 hours. We are not aware of any other reports of SPEX milling under similar conditions.…”

“…3 Typically SPEX milling is conducted in a mode that maximizes impact energy, as it is widely believed that low impact energy cannot induce alloying. 3 Therefore milling conditions that employ a few large (5 -8 g, 1.3 -1.5 cm diameter [6][7][8][9][10] ) balls are widely used. 3 Very nice results can sometimes be achieved under these conditions 10,11 but the resulting materials can also be microcrystalline as opposed to amorphous or nano-structured.…”

“…The microstructure of these alloys is critical to their electrochemical performance. 1,2,9,15 The existence of crystalline species will induce 2-phase coexistence during lithiation, resulting in immense stress along phase boundaries, crack propagation, electrical disconnection of alloy particles and, ultimately, severe capacity fade during charge/discharge cycling. 1,2 The electrochemical properties of such alloys are extremely sensitive to their microstructure and can be more sensitive than what is detectable by x-ray diffraction.…”

Rationally Designed Silicon Nanostructures as Anode Material for Lithium‐Ion Batteries

“…[38] Similar results have also been discovered on the Sn-based electrode, which suffers from an analogic volume variation as silicon material, that particles do not fracture further when the particle diameter is below the critical size. [39,40] The engineering techniques for silicon nanoparticles are rather mature and can be broadly classified into four categories: chemical vapor deposition (CVD) method, [41][42][43] ball-milling method, [44,45] molten salt electrolysis method, [46,47] and magnesiothermic (carbothermic) reduction method. [48][49][50] Si nanoparticles synthesized by CVD method usually enjoy a uniform particle dimension distribution.…”

“…[66][67][68][69][70] Scientists have developed several methods to produce Si/graphene composites for LIBs. In 2015, Feng et al proposed a facial way to fabricate of [46] Si NPs Ball milling -50 1354 (M-Si) 980 (F-Si) 41.5% (M-Si) 44.6% (F-Si) [45] Si NPs/C Spray drying 83.5 150 1366 (4 A g À1 ) 91% [53] Si NPs/C Hydrothermal 90.4 100 1607 (0.4 A g À1 ) 85% [56] Si NPs/C electrospinning 87.5 100 1305 (0.24 A g À1 ) %100% [59] Si NPs/C Mg reduction/CVD -500 1199 (0.5 A g À1 ) 86% [58] Si NPs /G/C Freeze drying/CVD 76.8 300 840 (1.4 A g À1 ) 76% [71] Si NPs /G Solvent evaporation/ reduction 47 50 1118 (0.05 A g À1 ) 66.3% [75] Si NPs/G Gel/coating/reduction 54 1300 668 (0.4 A g À1 ) 49.5% [69] Si NPs/G Freeze casting/ freezing drying/ reduction 78 1200 1170 (1 A g À1 ) 93% [92] Si NPs/PPy/CNT in situ polymerization 78.2 1000 1600 (3.3 A g À1 ) 86% [82] Si NPs/PANi in situ polymerization 70 1000 550 (6 A g À1 ) 91% [79] Si NPs/PEDOT: PSS in situ secondary doping 77.6 100…”