Extremely Accessible Potassium Nitrate (KNO3) as the Highly Efficient Electrolyte Additive in Lithium Battery

The systematic investigation of RNO3 salts (R = Li, Na, K, and Cs) as electrolyte additives was carried out for lithium-battery systems. For the first time, the abundant and extremely available KNO3 was proved to be an excellent alternative of LiNO3 for suppression of the lithium dendrites. The reason was ascribed to the possible synergetic effect of K+ and NO3– ions: The positively charged K+ ion could surround the lithium dendrites by electrostatic attraction and then delay their further growth, while simultaneously the oxidative NO3– ion could be reduced and subsequently profitable to the reinforcement of the solid-electrolyte interphase (SEI). By adding KNO3 into the practical Li–S battery, the discharging capacity was enhanced to average 687 mAh g–1 from the case without KNO3 (528 mAh g–1) during 100 cycles, which was comparable to the one with the well-known LiNO3 additive (637 mAh g–1) under the same conditions.