Recycled plastics are low-value commodities due to residual impurities and the degradation of polymer properties with each cycle of re-use. Plastics that undergo reversible polymerization allow high-value monomers to be recovered and re-manufactured into pristine materials, which should incentivize recycling in closedloop life cycles. However, monomer recovery is often costly, incompatible with complex mixtures, and energy-intensive. Here, we show that next-generation plastics-polymerized using dynamic covalent diketoenamine bonds-enable recovery of monomers from common additives, even in mixed waste streams. Poly(diketoenamine)s "click" together from a wide variety of triketones and aromatic or aliphatic amines, yielding only water as a byproduct. Recovered monomers can be re-manufactured into the same polymer formulation, without loss of performance, as well as other polymer formulations with differentiated properties. The ease in which poly(diketoenamine)s can be manufactured, used, recycled, and re-used-without losing value-points to new directions in designing sustainable polymers with minimal environmental impact. Closed-Loop polymer life cycles are critical to sustainability efforts worldwide. 1-7 Their integration into the global materials ecosystem hinges on maintaining high value in recovered materials at the end of a product's life.

The morphologies of sodium electrodeposits and gas evolution were studied in a system comprising a symmetrical Na/Na optical cell, a digital microscope, and an electrochemical workstation. Sodium deposition in ethylene carbonate (EC), diethyl carbonate (DEC), and propylene carbonate (PC) generated large volumes of gas and fragile, porous dendrites. The use of fluoroethylene carbonate (FEC) greatly reduced gassing during deposition and demonstrated superior cycling performance, impedance, and cycling efficiency when it was used as a cosolvent with DEC (1:1 vol); however, porous depositions persisted. Time of flight secondary-ion mass spectrometry revealed that the solid-electrolyte interphase formed in FEC/DEC, in contrast with the EC/DEC electrolyte, is thicker, richer in NaF, and forms a less dense polymer organic layer.

Capacity retention of anode-free cells, in which the cathode's lithium was the sole lithium source, was studied. These cells fail by depletion of their limited amount of cycling lithium, unlike cells with lithium foil anodes in which the buildup of an insulating, dead lithium layer on the anodes causes failure. The electrolyte dependence of the deposition morphologies was also studied optically in a symmetrical cell built with lithium electrodes. After passage of 28 mAh cm −2 , dendrite-free deposits were observed in a concentrated LiNO 3 electrolyte. SEI characterization revealed that this LiNO 3 concentrated electrolyte formed a Li 2 O enriched and organic polymer depleted interphase.

A simple one‐pot process for producing 3.5 nm diameter uniformly dispersed SnSb nanoparticles on a nitrogen‐doped carbon composite (NC) is reported. An ethanol slurry of SnCl4, SbCl3, and nitrilotriacetic acid (NTA) is heated in air to 300 °C to form the mixed metal oxide NTA complex; heating to 650 °C under argon yields the SnSb/NC nanocomposites, comprising 3.5 nm diameter SnSb nanocrystals uniformly distributed in the conductive N‐doped carbon. After 200 cycles at a specific current of 0.1 Ag−1, the SnSb/NC nanocomposite sodium‐ion anode retains a reversible capacity of 244 mAh g−1. The similarly prepared Sn/NC and Sb/NC anodes retain lower capacities of 88 and 188 mAh g−1, respectively. The improved performance of the SnSb/NC electrode might be ascribed to the stepwise sodiation/desodiation process of Sn and Sb species in the SnSb/NC electrode, which could act as an inert buffer matrix for each other, according to the potentials, slowing the capacity fading.