Silicon Quantum Dots Induce Uniform Lithium Plating in a Sandwiched Metal Anode

Abstract

Lithium (Li) metal anodes are demanded by high-energy Li batteries because Li has the highest capacity and low electrode potential. However, Li metal anodes usually show poor cyclability and unsafe deposition at anode/separator interfaces, which may increase the risk of short circuits. In this work, we fabricate a sandwiched structure of reduced graphene oxides (rGO) with silicon (Si) quantum dots (QDs) as the inducing agents between rGO layers. Because of the lithiophilicity of Si QDs, Li growth is favorably guided away from the unsafe anode/separator interface towards the interlayer positions, significantly improving the cyclability and safety of the Si-QDssandwiched rGO anode. The uniformly-distributed Si QDs and layered electrode structure can regulate Li plating/stripping to avoid the superficial Li growth and reduce the accumulation of solid electrolyte interphase. The growth-guiding strategy using the sandwiched structure provides a new approach to fabricating high energy Li-based battery anodes.

Recent progress in quantum dots based nanocomposite electrodes for rechargeable monovalent metal-ion and lithium metal batteries

“…260 Towards stabilizing the Li metal anode, QDs and QD based composites have been used as a matrix for dendrite-free lithium deposition, as a component in the solid-state electrolyte to improve the ionic conductivity, for increasing the Li + transference number and reducing interfacial resistance with lithium metal and as an electrolyte additive to regulate homogeneous lithium deposition at the anode. 55,261 One of the strategies to stabilize lithium metal is to guide the metal deposition away from the anode/electrolyte interface during charging. Metals such as gold (Au), zinc (Zn), silicon (Si), copper (Cu), cobalt (Co), etc.…”

“…Thus alloy nuclei with high lithiophilicity offer a low lithium-ion diffusion barrier and a dendrite-free anode can be realized. 264 Zhang et al 55 demonstrated such an engineered matrix constructed with Si QDs sandwiched between rGO sheets. Si is more lithiophilic than rGO and favors the Li nucleation and plating between rGO layers.…”

“…In addition, owing to a large number of abundant catalytic active sites and tuneable structural defects, QDs also possess catalytic properties towards the kinetic conversion between sulfur and polysulfides and inhibiting polysulfide shuttling in Li–S batteries 48–50 or kinetic conversion between O 2 and Li 2 O 2 in Li–air batteries. 51–53 QDs have also shown promising results in terms of regulating uniform and dendrite-free metal deposition at the anode 54–56 and improving the lithium-ion transport properties when used as fillers in solid-state electrolytes. 57,58…”

Strategies and challenges of carbon materials in the practical applications of lithium metal anode: a review

“…Matching the NMC532 (LiNi 0.5 Mn 0.3 Co 0.2 O 2 ) electrode, full battery cycle for 380 cycles has almost no capacity fading. Zhao et al 118 fabricated a sandwich structure between rGO layers using silicon quantum dots (SiQDs) as the lithiophilic inducing agents. The ultrafine size of SiQDs enables the parallel stacking of rGO layers without uneven grain inclusions.…”

CoSe2/MoS2 Heterostructures to Couple Polysulfide Adsorption and Catalysis in Lithium‐Sulfur Batteries†

“…[ 1‐4 ] However, the dissolution of intermediate polysulfides in the electrolyte leads to the rapid capacity fading and the corrosion of Li metal anode. [ 5‐7 ] What's worse, sluggish reaction kinetics of polysulfide conversion lower efficient utilization of sulfur species and lead to polysulfide accumulation, which would aggravate the shuttling effect. [ 8‐9 ]…”