Hopkins Brandon J, Sassin Megan B, Parker Joseph F, Long Jeffrey W, Rolison Debra R
Naval Research Laboratory, National Research Postdoctoral Associate, U.S. Naval Research Laboratory, Washington, DC, 20375, United States.
Surface Chemistry Branch, U.S. Naval Research Laboratory, Washington, DC, 20375, United States.
J Vis Exp. 2020 Sep 29(163). doi: 10.3791/61770.
We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized by creating a paste made of zinc particles, organic porogen, and viscosity-enhancing agent that is heated under an inert gas and then air. During heating under the inert gas, the zinc particles anneal together, and the porogen decomposes; under air, the zinc fuses and residual organic burns out, yielding an open-cell metal foam or sponge. We tune the mechanical and electrochemical properties of the zinc sponges by varying zinc-to-porogen mass ratio, heating time under inert gas and air, and size and shape of the zinc and porogen particles. An advantage of the reported methods is their ability to finely tune zinc-sponge architecture. The selected size and shape of the zinc and porogen particles influence the morphology of the pore structure. A limitation is that resulting sponges have disordered pore structures that result in low mechanical strength at low volume fractions of zinc (<30%). Applications for these zinc-sponge electrodes include batteries for grid-storage, personal electronics, electric vehicles, and electric aviation. Users can expect zinc-sponge electrodes to cycle up to 40% depth of discharge at technologically relevant rates and areal capacities without the formation of separator-piercing dendrites.
我们报告了两种制造锌海绵电极的方法，该电极可抑制可充电锌电池中枝晶的形成和形状变化。这两种方法的特点是制备一种由锌颗粒、有机造孔剂和增稠剂制成的糊状物，先在惰性气体中加热，然后在空气中加热。在惰性气体中加热时，锌颗粒一起退火，造孔剂分解；在空气中，锌熔化，残留的有机物燃烧殆尽，生成开孔金属泡沫或海绵。我们通过改变锌与造孔剂的质量比、在惰性气体和空气中的加热时间以及锌和造孔剂颗粒的尺寸和形状来调节锌海绵的机械和电化学性能。所报道方法的一个优点是它们能够精细调节锌海绵的结构。锌和造孔剂颗粒的选定尺寸和形状会影响孔结构的形态。一个局限性是所得海绵具有无序的孔结构，这导致在锌的低体积分数（<30%）下机械强度较低。这些锌海绵电极的应用包括用于电网储能、个人电子产品、电动汽车和电动航空的电池。用户可以预期锌海绵电极在技术相关的速率和面积容量下能够循环至40%的放电深度，而不会形成刺穿隔膜的枝晶。
