Protective membrane for electrochemical cells

An electrode, comprising:

• a first electroactive layer comprising a first electroactive material, wherein the first electroactive material comprises lithium metal prior to charge and discharge cycles;
• a composite protective layer adjacent the first electroactive layer, wherein the composite protective layer comprises a polymeric binder and particles dispersed in the polymeric binder, wherein the particles comprise boron particles, wherein the boron particles make up greater than or equal to 80 wt % of the composite protective layer, and wherein pores make up greater than or equal to 10 vol % of the composite protective layer;
• and
• a second electroactive layer comprising a second electroactive material adjacent the composite protective layer and positioned at a side of the composite protective layer opposite the first electroactive layer, wherein the second electroactive material comprises lithium metal prior to charge and discharge cycles, and wherein the second electroactive layer has a thickness that is greater than or equal to 1% and less than or equal to 50% of the thickness of the first electroactive layer;
• and
• an electrolyte adjacent the second electroactive layer, wherein the electrolyte is configured to permeate through at least a portion of the pores of the composite protective layer.