▎ 摘　　要

If an electrochemical energy storage device, which contains tetracyanoborate anions in the electrolyte, is accidentally charged with much higher voltage, it won't explode, because of a self-blocking mechanism. Firstly, voltage (E) more positive than 2.2 V (vs. Ag vertical bar AgCl reference electrode) kills the conductivity of single layer graphene and electrochemical reactions stop. Secondly, at E > 2.2 V tetracyanoborate anion polymerizes to a dielectric polymer polycyanoborani, which electrically isolates graphite or porous carbon grains from current collectors. (C) 2016 Elsevier B.V. All rights reserved.