Ultra-thick battery electrodes for high gravimetric and volumetric energy density Li-ion batteries

Abstract

Lithium-ion batteries, already capable of addressing the requirements of electric vehicles and renewable electricity storage, will be in the focus for the next decade. However, the transition from the small batteries for portable electronic to ultra-high capacity batteries requires safety improvements and cost-cutting efforts. Intensive research has been performed in the last three decades to optimize specific and volumetric capacity of electrodes. Recently the attention is focusing on increasing the electrodes areal capacity to enable the substantial reduction of the current collectors, porous separator, and electrolyte resulting in large gravimetric and volumetric energy density improvements as well as cost savings. Here we propose a lithium-ion battery based on thick, additive-free ceramic negative and positive electrodes, i.e. LTO (Li4Ti5O12) and LFP (LiFePO4), obtained by a solvent-free technology called powder extrusion moulding. Against all odds, the LTO/LFP cell based on these thick ceramic electrodes (areal capacity of 13.3 mA h cm−2) achieved the very high energy of about 23.9 mW h cm−2. Such an excellent performance, achieved simulating a typical day-night charge/discharge cycle, opens the way for the deployment of low cost, effective household (and small industry) energy storage in combination with photovoltaic energy harvesting.