Lead-free ceramic capacitor reaches high energy density in tests
Researchers adjusted the composition and insulating layers of a lead-free multilayer ceramic capacitor based on barium titanate and measured its energy storage. They report 19.8 joules per cubic centimetre of recoverable energy density and 89.3 percent efficiency under a specified electric field. Commercial production and long-term performance outside these tests remain separate questions.
Science··Night
A layered ceramic stores energy
The research tested a lead-free multilayer ceramic capacitor based on barium titanate. The team changed the composition at the atomic scale, added a silica coating around ceramic grains and introduced an insulating barrier near the electrodes. These changes were intended to control electrical losses and withstand stronger fields. The reported prototype reached 19.8 joules per cubic centimetre in recoverable energy density and 89.3 percent efficiency at a field of 1,421 kilovolts per centimetre.[1]
Other tests use different conditions
The team also investigated repeated charging and discharging and performance at elevated temperatures, under conditions distinct from the peak-energy measurement. Those separate operating conditions should not be combined into one performance figure. The device is a laboratory sample; manufacturing yield, cost and durability in real equipment remain questions. A capacitor stores and releases energy rapidly, but its results cannot be treated as a battery comparison without matching conditions.[1]
Cycling and discharge used separate conditions
In a separate million-cycle fatigue test, recoverable energy changed by less than 3 percent and efficiency by less than 1 percent. A discharge measurement at another electric field found that 90 percent of the released energy arrived in about 1.19 microseconds. These tests address repeatability and speed, respectively. Their conditions differ from the high-field measurement used for the peak energy-density figure.[1]
