Activated carbons derived from coconut shells as high energy density cathode material for Li-ion capacitors.

Akshay Jain,Rajasekhar Balasubramanian,Seeram Ramakrishna,Vanchiappan Aravindan,Srinivasan Madhavi,Sundaramurthy Jayaraman,Palaniswamy Suresh Kumar,M P Srinivasan

doi:10.1038/srep03002

Abstract

In this manuscript, a dramatic increase in the energy density of ~ 69 Wh kg−1 and an extraordinary cycleability ~ 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of ~ 60% mesoporosity derived from coconut shells (CS). The AC is obtained by both physical and chemical hydrothermal carbonization activation process, and compared to the commercial AC powders (CAC) in terms of the supercapacitance performance in single electrode configuration vs. Li. The Li-HEC is fabricated with commercially available Li4Ti5O12 anode and the coconut shell derived AC as cathode in non-aqueous medium. The present research provides a new routine for the development of high energy density Li-HEC that employs a mesoporous carbonaceous electrode derived from bio-mass precursors.

Highlights

In this manuscript, a dramatic increase in the energy density of, 69 Wh kg–1 and an extraordinary cycleability, 2000 cycles of the Li-ion hybrid electrochemical capacitors (Li-HEC) is achieved by employing tailored activated carbon (AC) of, 60% mesoporosity derived from coconut shells (CS)
Similar to the results for the single electrode configuration, ZHTP displayed longer discharge times compared to ZP and h. The third sample (HTP) in LiHEC assembly
The Li-HEC comprising ZHTP delivered a high energy density of, 69 Wh kg–1 compared to rest of the ACs tested such as ZP (,52 Wh kg–1), HTP (,36 Wh kg–1) and commercial AC powders (CAC) (,36 Wh kg–1)

Summary

ANALYTICAL TECHNIQUES POROUS MATERIALS APPLIED PHYSICS

Akshay Jain[1], Vanchiappan Aravindan[2], Sundaramurthy Jayaraman[2,3], Palaniswamy Suresh Kumar[2], Rajasekhar Balasubramanian[4], Seeram Ramakrishna[3], Srinivasan Madhavi2,5,6 & M. This clearly suggests that the tailoring of carbonaceous materials with appropriate pore sizes is very crucial to yield high performance materials The enhancement of such AC are mainly because of phase purity (Table T1) and high surface area with mesopores, which are required for easy access of the electrolyte solution and thereby enables facile adsorption/de-sorption of PF62 anions especially at high current rates[38]. Based on the electrochemical performance of both AC cathodes derived from CS (Li/AC) and spinel phase Li4Ti5O12 (Li/Li4Ti5O12, Figure S2, supporting information) in half-cell configuration under same current densities, the mass loading optimized and adjusted by the ratio of anode to cathode is 153.88, 152.91 and 152.41 for samples HTP, ZP, and ZHTP, respectively. The performance of sample P is found to be very inferior compared to the rest of the ACs; the powder is not been tested in Li-HEC configuration

Discussion

Methods

Findings

Additional information