In Situ Growth of MOFs on the Surface of Si Nanoparticles for Highly Efficient Lithium Storage: Si@MOF Nanocomposites as Anode Materials for Lithium-Ion Batteries

A simple yet powerful one-pot strategy is developed to prepare metal–organic framework-coated silicon nanoparticles via in situ mechanochemical synthesis. After simple pyrolysis, the thus-obtained composite shows exceptional electrochemical properties with a lithium storage capacity up to 1050 mA h g^–1, excellent cycle stability (>99% capacity retention after 500 cycles) and outstanding rate performance. These characteristics, combined with their high stability and ease of fabrication, make such Si@MOF nanocomposites ideal alternative candidates as high-energy anode materials in lithium-ion batteries

Metal–Organic Frameworks (MOFs) as Sandwich Coating Cushion for Silicon Anode in Lithium Ion Batteries

A novel metal–organic framework (MOF) sandwich coating method (denoted as MOF-SC) is developed for hybrid Li ion battery electrode preparation, in which the MOF films are casted on the surface of a silicon layer and sandwiched between the active silicon and the separator. The obtained electrodes show improved cycling performance. The areal capacity of the cheap and readily available microsized Si treated with MOF-SC can reach 1700 μAh cm^–2 at 265 μA cm^–2 and maintain at 850 μAh cm^–2 after 50 cycles. Beyond the above, the commercial nanosized Si treated by MOF-SC also shows greatly enhanced areal capacity and outstanding cycle stability, 600 μAh cm^–2 for 100 cycles without any apparent fading. By virtue of the novel structure prepared by the MOFs, this new MOF-SC structure serves as an efficient protection cushion for the drastic volume change of silicon during charge/discharge cycles. Furthermore, this MOF layer, with large pore volume and high surface area, can adsorb electrolyte and allow faster diffusion of Li⁺ as evidenced by decreased impedance and improved rate performance

Customized Electrolyte and Host Structures Enabling High-Energy-Density Anode-Free Potassium–Metal Batteries

Potassium shows great potential to replace lithium in energy storage for its high abundance and comparable energy density. However, issues including an unstable interphase, dendrite growth, and volume change restrict the development of potassium metal batteries, and so far, there is no single cure that works once and for all. Here an anode-free potassium metal battery is demonstrated by introducing a customized electrolyte and host structures that simultaneously promote efficiency, reversibility, and energy density. First, a diluted high-concentration electrolyte with fast kinetics and high stability triggers an inorganic-rich durable interphase. Meanwhile, a carbonaceous host containing narrowly distributed mesopores (MCNF) favors reduced surface area but enough inner space. Together, they achieve a high average Coulombic efficiency (CE) of 99.3% and an initial CE of 95.9% at 3 mA cm–2–3 mA h cm–2. Anode-free MCNF||Prussian blue (PB) potassium cells are delivered with 100 reversible cycles and a high energy density of 362 W h kg–1