Five-volt-class high-capacity all-solid-state lithium batteries

Abstract

Advances in battery technology have been impeded by the voltage constraints of electrolytes. Here we present a high-energy all-solid-state battery design featuring >5 V operation and an ultrahigh areal capacity of 35.3 mAh cm(-2); these attributes were enabled by a highly conductive and ultrahigh-voltage stable fluoride solid electrolyte, LiCl-4Li(2)TiF(6) (1.7 x 10(-5) S cm(-1) at 30 degrees C). LiCl-4Li(2)TiF(6) shields high-voltage spinel oxide cathodes, achieving 106 mAh g(-1) at 2C with 75.2% retention over 500 cycles for LiNi0.5Mn1.5O4, sharply contrasting with the conventional LiNbO3 counterpart, which decomposes and fails to prevent detrimental interfacial degradation. The efficacy of LiCl-4Li(2)TiF(6) is validated across various systems, including LiCoMnO4, LiFe0.5Mn1.5O4 and pouch-type LiNi0.5Mn1.5O4||Li (or Ag-C) all-solid-state batteries, and further demonstrated by operability down to 2.3 V with 258 mAh g(-1) and ultrathick 1.8-mm electrodes. This shielding layer with >5 V stability introduces a transformative design paradigm by revisiting the previously forbidden high-voltage cathodes.